ASH NEWS AND REPORTS®
MARCH/APRIL 2016
VOLUME 13 ISSUE 2
D I F F U S I O N
The TWiTCH Trial
Ware RE, Davis BR, Schultz WH, et al. Hydroxycarbamide versus
chronic transfusion for maintenance of transcranial doppler
flow velocities in children with sickle cell anaemia-TCD With
Transfusions Changing to Hydroxyurea (TWiTCH): a multicentre,
open-label, phase 3, non-inferiority trial. Lancet. 2016;387:661-670.
I
n children with sickle cell disease, one of the most devastating
long-term sequelae is a stroke. Prior to 1998, approximately
11 percent of the children with sickle cell disease would have
strokes. Unfortunately for the majority of children, the only option
of secondary stroke prevention was the burdensome responsibility of
monthly blood transfusion therapy followed by the eventual requirement
of iron chelation therapy. Without regular blood transfusion therapy,
approximately 50 percent of the children would have a stroke recurrence
within two years of the initial stroke, and a significant proportion would
go on to have a third stroke or additional strokes. In 1998, the landmark
STOP trial demonstrated that among children with sickle cell disease
and elevated transcranial Doppler (TCD) measurements, regular blood
transfusion therapy (experimental arm) resulted in a 92 percent relative
risk reduction in strokes when compared with observation (standard
arm). The impact of implementing TCD screening coupled with blood
transfusion therapy has resulted in up to a log-fold decrease in the rate
of strokes in children with sickle cell disease. However, the impact of
decreasing the rate of strokes is not without its consequences, and the
most significant of these is the commitment to lifelong blood transfusion
therapy and chelation therapy for the majority of children treated with
elevated TCD velocities.
With this background, Dr. Russell Ware and colleagues completed a
randomized, open-label, noninferiority trial referred to as the TWiTCH
(TCD With Transfusions Changing to Hydroxyurea) trial. The team
tested the hypothesis that children with elevated TCD measurements
(> 200 cm/sec nonimaging technique) who had been placed on
blood transfusion therapy for primary stroke prevention could be safely
switched to hydroxyurea therapy. The two arms of the trial were regular
blood transfusion therapy with iron chelation (standard arm) versus
hydroxyurea therapy and phlebotomy (experimental arm). The primary
endpoint was the 24-month TCD velocity with a non-inferiority margin set
at 15 cm/sec. A minimum of 12 months of blood transfusion therapy for
elevated TCD measurements were required for inclusion and individuals
with severe magnetic resonance angiogram-defined vasculopathy
were excluded from the trial. The Data and Safety Monitoring Board
stopped the trial early because of the convincing evidence that the
experimental arm was noninferior to the standard arm. Significantly,
no strokes occurred in either arm, as would be expected because the
stroke event rate in children with elevated TCD measurements treated
with blood transfusion therapy is very low (0.06 to 0.9 events per 100
patient years), and the trial had a short follow-up with only 121 total
participants. For children who met the inclusion and exclusion criteria,
the main conclusion of the trial is that for children with sickle cell disease
and high TCD velocities, maximum tolerated dose of hydroxyurea therapy
is noninferior to blood transfusion.
This is a landmark trial that will have a lasting impact on primary
prevention of strokes in thousands of children in high-income countries.
Due to the early cessation of the trial, the remaining question is the
permanence of hydroxyurea therapy for primary stroke prevention in
children with elevated TCD measurements. Hopefully the investigators
can continue to formally follow TWiTCH participants for a longer span
of time to determine the long-term benefits and risks, if any, of being
treated for an indefinite period on hydroxyurea therapy.
Since 1998, the ability to now complete the fifth National Institutes of
Health–sponsored randomized clinical trial for primary or secondary
stroke prevention in children with sickle cell disease should lay to rest
the perception that the African American community is unwilling to
participate in patient-oriented research. The community will participate
when there is a compelling research question to be answered, coupled
with a trusted provider network.
MICHAEL R. DEBAUN, MD
Professor Theodor Fliedner and
the Atomic Hematologists
ROBERT PETER GALE, MD, PhD, FACP, 1 AND DIETER HOELZER, MD, PhD 2
1. Visiting Professor, Haematology Research Centre, Division of Experimental Medicine, Department of Medicine,
Imperial College London, London, UK
2. Professor of Medicine, MD, PhD, FACP, Department of Hematology/Oncology and Infectious Diseases, J.W. Goethe
University Hospital, Frankfurt, Germany
The era of the atomic hematologists came to an end with the
recent death of Professor Theodor M. Fliedner in Ulm, Germany, on
November 9, 2015. Most readers of The Hematologist won't know
of this important chapter in hematology research led by a cadre
of talented physician-scientists whose careers were profoundly
influenced by the atomic age, much less how bikinis got their name or how to make beer taste the
same glass to glass.
Fliedner was born in Hamburg in 1929 during an exciting time in physics and radiation biology
in Europe and especially in Germany, with Albert Einstein, Leó Szilárd, Max Planck, Werner
Heisenberg, Erwin Schrödinger, Herman Hemholtz, and others still active. In 1945, when Fliedner
was 16, the United States dropped the atomic bombs on Japan to end World War II. This event
had a tremendous influence on Fliedner, sparking his interest in the effects of ionizing radiation
on animals and humans, especially the effects on hematopoiesis and hematopoietic stem cells.
He studied medicine at the Universities of Göttingen and Heidelberg where he graduated summa
cum laude. His doctoral thesis was titled “On the Pathogenesis of Acute Bone Marrow Atrophy in
Rats After Whole Body Irradiation with Fast Electrons.” (How fast is “fast?” About 100,000 km/sec
or about one-third the speed of light.) After graduation and postdoctoral training, he established a
radiation hematology research unit in the Czerny-Hospital in Heidelberg.
In 1957, Fliedner went to the Brookhaven National Laboratory in Long Island where Dr. Eugene P.
Cronkite (see photo on page 3) and colleagues were working on radiation-related health issues.
The United States had been conducting a series of nuclear tests at the Bikini and Enewetak Atolls
in the Marshall Islands from 1946 to 1958.a
The “Castle Bravo” test of 1954 was of unanticipated intensity (a 15-megaton thermonuclear bomb
1,000 times more powerful than the Hiroshima bomb). Unfortunately, about 300 Marshallese then
living on the Rongelap, Ailinginae, and Utrik Atolls were exposed to radioactive fallout, principally
iodine-131 (131I) and cesium-137 (137C). The Brookhaven team was involved in studying and treating
the victims. This intrigued Fliedner immensely.
Development of atomic bombs and associated events played important roles in the identification
of hematopoietic stem cells and unraveling the structure and kinetics of hematopoiesis. In 1945,
the existence of hematopoietic stem cells was postulated but unproved. Fliedner, Cronkite,
and others such as László Lajtha (Holt Radium Institute); Nicole Muller-Bérat Killman and SvenAage Killman (State Serum Institute,
Copenhagen, Denmark); Dane Boggs
(University of Pittsburgh); Frederick
Stohlman Jr. (Tufts University); George
Brecher (National Institutes of Health);
and Maxwell Wintrobe, George Cartwright,
John Athens, and Alvin Mauer (University
of Utah) tackled the question in diverse
research models such as giving animals
and humans (mostly prisoners) tritiated
thymidine (3H-thymidine) and 32P-labeled
diisopropyl-fluorophosphate (DFP32).
You would be arrested if you tried these
experiments today. The thymidine for these
experiments was provided by the Schwartz
Chemical Company, which made yeast
for beer brewers.b These radionuclides
were injected and samples were taken for
autoradiography and radiochemical assays.
Autoradiography at that time required
counting a few grains over hundreds of cell
nuclei under a light microscope – tedious
and demanding (imagine the worst Southern
blot you have ever seen then multiply by
(Cont. on page 3)
Dr. DeBaun indicated no relevant conflicts of interest.
4
ASK THE HEMATOLOGIST – Dr. Sigbjorn
Berentsen describes the management of
primary cold agglutinin disease.
6
MINI REVIEW – Drs. Virginia Yao, Renata
Pasqualini, and colleagues explore “zip
codes” for targeted drug design.
13
PERSPECTIVE – Dr. W. Keith Hoots
discusses cross-cutting science at NHLBI’s
Division of Blood Diseases and Resources.
14
CLINICAL TRIALS CORNER –
Dr. Theresa Coetzer summarizes the
N-PhenoGENICS trial.
President’s Column
Hematologist
THE
ASH NEWS AND REPORTS®
ISSN 1551-8779
PUBLISHED BIMONTHLY
Editor-in-Chief:
Jason Gotlib, MD, MS
Stanford Cancer Institute
Stanford, CA
Contributing Editors:
Omar Abdel-Wahab, MD
Memorial Sloan-Kettering Cancer Center
New York, NY
Theresa Coetzer, PhD
University of the Witwatersrand
Johannesburg, South Africa
Adam Cuker, MD, MS
University of Pennsylvania
Philadelphia, PA
Michael DeBaun, MD
Vanderbilt University
Nashville, TN
David Garcia, MD
University of Washington
Seattle, WA
Tracy I. George, MD
University of New Mexico
Albuquerque, NM
Jonathan Hoggatt, PhD
MGH/Harvard University
Cambridge, MA
Sioban Keel, MD
University of Washington
Seattle, WA
Ann LaCasce, MD, MSc
Dana-Farber Cancer Institute
Boston, MA
Paul Moss, MBBS, PhD, FRCP
University of Birmingham
Birmingham, United Kingdom
Elizabeth Raetz, MD
University of Utah
Salt Lake City, UT
How ASH Spreads the News
I
n an increasingly connected, information-driven society, the impressions we make each day and the conversations
in which we take part — our “footprints” in the world at large — are of utmost importance. With this in mind, ASH
expends a great deal of effort to maintain awareness of the larger conversation around hematologic breakthroughs and
developments, to consistently share information that directly affects the community of hematologists, and also to lead
these conversations when it is most appropriate.
It is worth mentioning that early in my tenure with ASH, the Society purposely kept a low profile, operating under
the assumption that the science should speak for itself. But in the last 12 years, ASH leadership has recognized the
importance of raising the profile of hematology in order to help support a number of strategic goals — specifically,
ensuring the future of hematology and promoting the best care of patients. To that end, ASH has built a comprehensive
strategy to foster healthy interactions with the trade and lay press, which includes sustaining and tapping into our media
relationships before, during, and after the annual meeting.
If you attended the most recent meeting, you couldn’t miss the proverbial “gauntlet” of reporters in the halls of the
Orange County Convention Center. The 2015 ASH annual meeting drew an impressive 271 reporters (96 U.S. and 175
international), from top-tier news sources including Bloomberg, Reuters, and The Wall Street Journal, which ran the
widely circulated story “New Weapons in the Fight Against Multiple Myeloma.” And for the second year in a row, CNBC
broadcast live from the meeting. Through the presence of these and other outlets, a greater public appreciation for the
important work we do is created, and a deeper understanding of major scientific breakthroughs — from newly approved
drugs, to CAR T cells, to gene therapy for sickle cell disease — moves far and wide throughout society.
Similar to the annual meeting, the influence of Blood is always top of mind in terms of maintaining and increasing our
visibility in the public eye. When a Blood article gains momentum in the popular press, important conversations are
sparked. For example, back in 2013, ASH published a Blood Forum article in which more than 120 experts in CML wrote
that the high cost of drugs is “unsustainable.” News of this timely, controversial, and consumer-friendly piece appeared
in 323 stories in outlets such as The New York Times, CBS Evening News, CNN, Consumer Reports, CNN Money, Forbes,
and Harvard Business Review, and stimulated a critical national dialog about the sometimes crippling prices of live-saving
drugs.
There has been much discussion lately about the exciting times that we are witnessing in hematology, and the ground
that is being broken in drug development, genome editing, and numerous other areas. With this whirlwind of innovation
comes a flood of information that can overwhelm not only us as practitioners, but also the patients and families that
we are united in serving. ASH is dedicated to disseminating the most credible, clear, informative news in the field, and
to harnessing all our media relationships to do the essential work of educating the broader public and elevating the
perception of hematologists and all that we do.
Noopur Raje, MD
Massachusetts General Hospital
Boston, MA
Managing Editor
Juana Llorens, MS
Charles Abrams, MD
Editorial Associate
Laura M. Santini
Graphic Designer
grayHouse design
American Society of Hematology
2021 L Street, NW, Suite 900
Washington, DC 20036
jllorens@hematology.org
LETTERS TO THE EDITOR SOLICITATION
©2016 by the American Society of Hematology.
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The material published in The Hematologist is for
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2
CORRECTION:
In the January/February 2016 article, “57th ASH Annual Meeting
Wrap-Up,” on page 4, there is an incorrect statement. The
phrase should read “daratumumab, a monoclonal antibody to
CD38,” not “CD138.” This has been corrected online, and we
apologize for this error.
Juana Llorens, Managing Editor
The Hematologist: ASH News and Reports
2021 L Street, NW, Suite 900
Washington, DC 20036
jllorens@hematology.org
The Hematologist:
ASH NEWS AND REPORTS
N E W S
A N D
R E P O R T S
Theodor Fliedner
(Cont. from page 1)
1,000). However, Fliedner was an expert, and as recounted by
Cronkite in his 1989 oral history for ASH,d he was often found
in the lab at 4:00 a.m. laboring over an autoradiograph. He also
studied bone marrow transplants in dogs given high doses of
nitrogen mustard, in collaboration with Dr. E. Donnall Thomas,
then at Cooperstown, New York. Using this model, Fliedner was
able to show that a large proportion of hematopoietic stem
cells were in the resting stage of the cell cycle.
New Location: Highlights of ASH Latin America
Improve your patient management and care strategies by attending Highlights of ASH in Latin America in Porto
Alegre, Brazil. Hear internationally recognized experts analyze the latest updates in hematology research from
the 57th ASH Annual Meeting. This is your chance to evaluate your diagnostic techniques and therapeutic
approaches and discuss with leading hematology experts and colleagues how new research and clinical
updates can be translated into new patient care strategies. Simultaneous translations into Spanish and
Portuguese will be available at this meeting.
Program Co-Chairs
Dr. Eduardo Rego, University of São Paulo
Dr. Carlos Chiattone, The Santa Casa Medical School, São Paulo
The meeting will take place April 29-30, 2016, at the FIERGS Exhibition & Convention Centre. Learn more at
www.hematology.org/Highlights/Latin-America.aspx
ASH Meeting on Lymphoma
Biology
The 2016 ASH Meeting on Lymphoma Biology
will take place June 18-21 at The Broadmoor
in Colorado Springs, CO. The meeting brings
together experts from around the world to discuss
the latest breakthroughs in basic and translational
lymphoma research. Learn about current
challenges in the field and exchange ideas on how
to move the field forward. Laboratory-based and
pharmaceutical scientists, translational and junior
investigators, and other health professionals will
be able to establish collaborations with leading
experts and colleagues and earn CME credits.
Visit www.hematology.org/Lymphoma-Biology/ for
more information and to register.
ASH Workshop on Genome Editing
ASH’s Workshop on Genome Editing will be held July 14-15, 2016, in Washington, DC. This is a new
opportunity to discuss current genome targeting methodologies; outline vital steps necessary to improve the
specificity, efficacy, and versatility of these methods; and highlight the transformative potential of genome
editing in basic and clinical research for hematology and beyond. The program will include a review of ongoing
clinical trials; present examples of application of genome editing technology; and provide additional information
on regulatory frameworks, use of this technology as a research tool, and successful translation into the clinic.
It will also provide a platform for the exchange of ideas and encourage strategic collaborations among all
stakeholders interested in this technology. Registration is now open, and more information is available at
www.hematology.org/Genome-Editing.
ASH Meeting on Hematologic Malignancies
This year’s ASH Meeting on Hematologic Malignancies will take place September 15-17 in Chicago, IL.
Attendees will have the opportunity to hear world-class experts in hematologic malignancies discuss the latest
developments in clinical care and learn how to treat their own patients through “How I Treat” sessions. These
sessions will cover core malignancies including leukemia, lymphoma, myelodysplastic syndromes, myeloma,
and myeloproliferative neoplasms. All program speakers have been announced. For more information and a full
list of speakers, visit www.hematology.org/Malignancies/.
This brings us to bone marrow transplants and the atomic
bomb. Several U.S. physicians, including hematologists, were
part of the Manhattan Project (see
photo on page 5), which developed
the atomic bombs detonated over
Japan in 1945. These participants
included Louis Hempelmann,
who treated victims of a famous
criticality accident at Los Alamos.c
Immediately after World War II,
the U.S. government, especially the
Navy, which had nuclear submarine
and aircraft carrier programs, was
anxious to find ways to reverse the
destruction of the bone marrow
Dr. Eugene P. Cronkite
caused by exposure to high doses
of ionizing radiations. The fear was that a nuclear attack by
the Russians or a submarine accident would have devastating
effects on military forces and on civilians. Hematologists were
assembled at several sites including the National Institutes of
Health and the University of Chicago. These efforts led to many
important discoveries, including transplanting bone marrow
cells into irradiated animals by Dr. Egon Lorenz and colleagues,
and later into humans, as pioneered by researchers including
Drs. E. Donnall Thomas, Joseph Ferrebee, and Georges Mathé,
who with his colleagues in Paris treated five victims of a nuclear
reactor accident in Vinča, Yugoslavia, in 1958. These radiationrelated studies also led to the discovery of hematopoietic
growth factors such as erythropoietin by Drs. Alan Erslev,
Eugene Goldwasser, and others, and of myeloid growth factors
by Drs. Leo Sachs and Dov Pluznik in Israel, Drs. Benjamin
Bradley and Donald Metcalf and colleagues in Melbourne,
and Dr. Malcolm Moore and colleagues in New York. Similar
radiation protection programs were started in Europe, including
in the Netherlands at the TNO, the Netherlands Organisation for
Applied Scientific Research, by Dirk van Bekkum.
Much of what we know regarding the etiology of leukemias
and related disorders also comes from studies done by the
atomic hematologists. An increase in leukemia was first noted
by Japanese hematologist Dr. Takuso Yamawaki in the late
1940s. This led to the establishment of the joint Japan-US
Atomic Bomb Casualty Commission (now the Radiation Effects
Research Foundation) in 1950 and the start of the Life-Span
Study of 121,000 exposed persons and controls conducted by
Japanese and American hematologists and epidemiologists.
These data provide the most convincing evidence that
ionizing radiations cause leukemias, and the dose-response
relationships developed from these studies are the basis of
most radiation protection guidelines. Hematologists such
as Dr. Masao Tomonaga have spent their lives studying
hematologic consequences of the atomic bombings.
Back to Fliedner. In 1963 he returned to Europe to become
director of EURATOM Institute for Radiation Hematology
Research affiliated with the Faculty of Medicine at the
University of Freiburg. He and his team studied the behavior
of resting hematopoietic stem cells in rats using a model
of continuous 3H-thymidine infusion. They were able to
distinguish resting and dividing stem cells and their progeny
and postulated that the resting stem cells were attached to the
bone marrow endothelium. This prescient observation is the
basis of much of the current research into the so-called stem
cell niche (see Diffusion article in this issue by Dr. Jonathan
Hoggatt), a field most people think was recently invented.
Their model was also applied to other settings such as highdose radiation exposures and leukemia. These experiments
in rodents and dogs required a continuous 24- to 48-hour
3
H-thymidine infusion, and the team often spent nights and
weekends in the laboratory.
Fliedner’s interest in hematopoietic stem cells and radiation
naturally led to studies of leukemia. He considered both
sides of the issue: radiation as a cause of leukemia and using
radiation to treat persons with leukemia. His team developed a
technique of extracorporeal radiation as a therapy in persons
with chronic lymphocytic leukemia (CLL), whereby blood was
shunted into a chamber and exposed to ionizing radiations.
Because lymphocytes are killed by radiation in interphase
(Cont. on page 5)
The Hematologist:
ASH NEWS AND REPORTS
3
ASH does not recommend or endorse any specific tests, physicians, products, procedures, or opinions, and disclaims any representation, warranty, or guaranty as to the same. Reliance on any information
provided in this article is solely at your own risk.
Ask the Hematologist
SIGBJORN BERENTSEN, MD, PHD
Consultant, Department of Research and Innovation, Haugesund Hospital, Helse Fonna; Haugesund, Norway
The Question
What is your management approach to patients with primary cold agglutinin disease?
My Response
Primary chronic cold agglutinin disease (CAD) is an autoimmune hemolytic anemia
mediated by cold agglutinins (CA), without any obvious underlying disease such as
aggressive lymphoma, other overt malignancies, or specific infections.1,2 CA are able to
agglutinate red blood cells (RBC) at an optimum temperature of 3°C to 4°C, but are also
active at higher temperatures, depending on the thermal amplitude.1 Most CA in CAD
are IgMκ antibodies and have specificity for the surface carbohydrate antigen termed I,
whereas IgG, IgA, or λ phenotype are found in less than 10 percent of cases.2
Classification
CAD is a well-defined clinicopathologic entity, as described below, and should be called
a disease, not syndrome.1 The term “cold agglutinin syndrome” (CAS) should be used
for secondary CA-mediated hemolytic anemia occasionally complicating other specific
clinical diseases, in particular Mycoplasma or Epstein Barr virus infection, or aggressive
lymphomas.
Clonality and Histopathology
Monoclonal serum immunoglobulin (usually IgMκ) can be detected in 90 percent of
patients with CAD, provided correct handling of samples and the use of immunofixation
even when capillary or agarose electrophoresis does not show any obvious spike.2 By flow
cytometry, the cellular κ/λ ratio in bone marrow aspirate is usually greater than 3.5.2
Our understanding of the immunohistologic and cellular basis of the clonal
immunoglobulin production has greatly improved during the last decade. Two large
series have confirmed signs of a clonal lymphoproliferative bone marrow disorder
in most patients.2,3 The individual hematologic and histologic diagnoses, however,
showed a striking heterogeneity within each series. In one study, lymphoplasmacytic
lymphoma (LPL) was the most frequent finding, whereas marginal zone lymphoma (MZL)
and unclassified clonal B-cell lymphoproliferation were also reported frequently. The
explanation for this perceived heterogeneity has probably been revealed by a recent,
comprehensive study of 54 patients with CAD.4 The bone marrow findings in these
patients were consistent with a surprisingly homogeneous disorder, termed by the
authors “primary CA-associated lymphoproliferative disease”, which was distinct from
LPL, MZL, and other previously recognized entities. The MYD88 L265P mutation, found in
most cases of LPL, could not be detected in 15 samples from CAD patients analyzed for
this mutation.4,5
Mechanisms of Complement-Mediated Hemolysis
Following CA-binding to the I antigen at the RBC surface, the antigen-antibody complex
binds complement protein complex C1 and thereby triggers the classical complement
pathway.6 The Figure shows the details of this process, resulting in predominantly
extravascular, C3b-mediated hemolysis.6,7 Intravascular hemolysis mediated by the
C5b6789 complex has also been shown to occur to some extent, at least in some patients
and situations.6,8
Clinical Features and Diagnostic Workup
CAD is defined by chronic hemolysis, positive direct antiglobulin test (DAT), monospecific
DAT positive for C3d, and CA titer ≥ 64 (much higher in most cases).1,2 DAT is usually
negative for IgG but may be weakly positive.2
Approximately 90 percent of patients have cold-induced acrocyanosis and/or Raynaud
phenomena.2 By definition, all patients have hemolysis, but occasional patients are not
anemic because the hemolysis is fully compensated. Median hemoglobin (Hb) level has
been estimated at 8.9 g/dL.2 In cold climates, a majority of individuals experience seasonal
variations with worsening of anemia and circulatory symptoms during winter or at low
ambient temperatures.9 At least 70 percent of patients have experienced exacerbations
precipitated by febrile infection, major surgery, or major trauma.1,2,10 Fifteen percent or
more have hemoglobinuria.3 In a retrospective study, approximately 50 percent of patients
were transfusion-dependent at some time during the course of the disease.2
A focused history and clinical examination is, therefore, an essential part of the diagnostic
workup. Quite often, “the history tells you the diagnosis.” Laboratory tests should
include full blood counts, blood smear analysis, assessment of hemolysis (absolute
reticulocyte count, lactate dehydrogenase, bilirubin, and haptoglobin), polyspecific and
4
monospecific DAT, and CA titer. For differential diagnostic considerations, cryoglobulin
assessment should be included. Thermal amplitude determination may be of interest but
is time-consuming and often not necessary in routine clinical practice. Results of serum
electrophoresis with immunofixation, immunoglobulin class quantification, complement
protein (C3 and C4) levels and bone marrow examination (biopsy and flow cytometry) are
not part of the disease definition, but should always be obtained.1-4
Of critical importance, serum for CA titration, electrophoresis, and immunoglobulin
assessments must be obtained from blood specimens that have been kept at 37°C to 38°C
from the time of sampling until serum has been removed from the clot.1
Management
The mainstay of nonpharmacologic management is warm clothing and avoidance of cold.
Most patients, however, have discovered this measure before they see the hematologist.
Transfusions can be given safely provided that specific precautions are observed; these
are comprehensively described elsewhere.1 Splenectomy is inefficient because most of
the extravascular hemolysis takes place in the liver.1-3 Because almost all IgM is located
intravascularly, plasmapheresis is considered an efficient “first-aid” in acute situations or
before surgery requiring hypothermia.1 However, such remissions are short-lived.
Not all patients require drug therapy. In our opinion, however, pharmacologic treatment
is indicated more frequently than traditionally advised in the literature and should be
offered to patients with symptom-producing anemia or disabling circulatory symptoms.
Recommendations to avoid drug therapy have often been based on poor efficacy (until the
last 10 to 15 years), combined with an underestimation of the patients’ clinical problems.1,2
In two retrospective studies from Norway and the US, respectively, 70 to 80 percent of
the patients had received pharmacologic therapy.2,3 Corticosteroids are inefficient, and
unacceptably high maintenance doses are usually required to maintain remission in the few
responders.1-3 Corticosteroids should, therefore, not be used to treat CAD.
Two prospective trials of rituximab monotherapy (375 mg/m2 weekly for four weeks)
showed response rates of about 50 percent according to strict criteria.11,12 Complete
responses were rare. The median response duration was approximately one year. A
retrospective, “real life” study confirmed these findings.2 Based on these results and its very
favorable safety profile, rituximab monotherapy is now often recommended as first-line
treatment.13
The safety and efficacy of combination therapy with fludarabine and rituximab were studied
in 29 patients in a prospective trial.14 The participants received rituximab 375 mg/m2 on
days 1, 29, 57, and 85; and fludarabine 40 mg/m2 orally on days 1 to 5, 29 to 34, 57 to 61,
and 85 to 89. The same response criteria were used as in the rituximab monotherapy trial.
Twenty-two patients (76%) responded, with six (21%) achieving complete response and 16
(55%) achieving partial response. Median time to response was four months. An impressive
estimated median response duration of more than 66 months was achieved. Short-term
hematologic toxicity was significant, however, with 12 patients (41%) experiencing grade 3
or 4 toxicity. Furthermore, although not directly observed in this study, the possibility of
long-term toxicity may be a concern, particularly in younger patients.
In conclusion, patients with CAD requiring therapy should be included in prospective trials
if available. Outside clinical trials, fludarabine-rituximab combination therapy should be
considered in those who definitely need efficient treatment, especially if they have failed
rituximab monotherapy, are not too young, are reasonably fit, and have not previously
received cytotoxic chemotherapy. In patients failing to meet these criteria, single-agent
rituximab should remain first-line treatment.
The Future
Favorable response to bendamustine-rituximab combination therapy has been reported
in one patient, and a prospective study is ongoing.15 The targeted B-cell receptor pathway
inhibitors ibrutinib and idelalisib have not been evaluated in CAD.
Given that hemolysis in CAD is entirely complement-dependent,1,6 studies of complement
modulators are highly interesting. Favorable effect of the C5 inhibitor eculizumab has
been described in a prospective trial.8 Since the hemolysis is predominantly C3b-mediated
in most patients, complement blockade at a more proximal, classical pathway level
might, in theory, be more successful.6,7 Preclinical studies with the anti-C1s monoclonal
antibody TNT003 and its humanized counterpart TNT009 have shown favorable results.7
If sufficient clinical documentation for complement-directed therapies can be provided,
such treatment will probably still not replace clonally directed therapies, which are more
causal and do not need to be continued indefinitely. Complement-directed therapies
seem very promising, however, in acute exacerbations, in patients undergoing surgery
requiring hypothermia, and in those with severe CAD not responding to clonally directed
immunochemotherapy.
The Hematologist:
ASH NEWS AND REPORTS
T H E
P R A C T I C I N G
H E M A T O L O G I S T
Theodor Fliedner
(Cont. from page 3)
(G0 phase), blood counts fell precipitously. Interestingly, there were also off-target
(abscopal) effects such as reduced spleen and lymph node sizes. For perspective, Drs.
Kanti Rai and Rainer Storb treated persons with CLL with this technique when they
were fellows. This approach was abandoned when anti-leukemia drugs were developed
but is still biologically fascinating.
Figure
In 1967 the new Ulm University was inaugurated, with Fliedner as the youngest of eight
founders. He became the director of the Department of Clinical Physiology and later
the Dean of the Theoretical Faculty of Medicine. In 1983 he was appointed President
of the University of Ulm. His research group, staffed by associates from Europe and
elsewhere, focused on characterizing hematopoietic stem cells, especially after total
body radiation in dogs. The team showed that large numbers of hematopoietic stem
and progenitor cells could be collected by continuous-flow centrifugation, frozen, and
stored for a future transplant. Although their focus was on radiation accidents, these
techniques are currently used in auto transplants for cancer, especially lymphomas
and myeloma. Fliedner was often the volunteer for these experiments — he loved long,
tedious, technically demanding experiments.
In later life, Fliedner was best known internationally for his work on evaluating victims
of radiation accidents. He chaired a European Consortium of Experts, which developed
the 1981 publication Manual on the Acute Radiation Syndrome, which is widely used
today. Quite remarkably, he developed a database of more than 800 detailed reports of
radiation accidents. He also led a German research team studying the effects of space
travel on bone marrow function in humans — studies continued by NASA and the Japan
Space Agency.
Ted was active in scientific research throughout his life. Three years ago, he asked one
of the authors (Dr. Gale) for details regarding a radiation accident in Israel. He wanted
to review the pathology slides himself. In 2008, at age 79, he was writing letters to the
editor of Blood, and in 2012, at age 83, he was first author of an article in the journal
Dose-Response, “Hemopoietic Response to Low Dose-Rates of Ionizing Radiation Shows
Stem Cell Tolerance and Adaption.”
Complement-mediated hemolysis in cold agglutinin disease. Abbreviations: CA, cold
agglutinin; C, complement. Originally published in Biomed Res Int (Berentsen S, Sundic T.
Red blood cell destruction in autoimmune hemolytic anemia. Biomed Res Int. 2015;363278).
Copyright: S. Berentsen and T. Sundic. Re-used with permission.
Off-label use of pharmacological substances has been discussed. Dr. Berentsen has
received research support from Mundipharma, lecture honoraria from Alexion, and
consultancy honoraria from True North Therapeutics.
1. Berentsen S, Randen U, Tjønnfjord GE. Cold agglutinin-mediated autoimmune hemolytic anemia.
Hematol Oncol Clin North Am. 2015;29:455-471.
2. Berentsen S, Ulvestad E, Langholm R, et al. Primary chronic cold agglutinin disease: a population
based clinical study of 86 patients. Haematologica. 2006;91:460-466.
3. Swiecicki PL, Hegerova LT, Gertz MA. Cold agglutinin disease. Blood. 2013;122:1114-1121.
4. Randen U, Trøen G, Tierens A, et al. Primary cold agglutinin-associated lymphoproliferative
disease: a B-cell lymphoma of the bone marrow distinct from lymphoplasmacytic lymphoma.
Haematologica. 2014;99:497-504.
5. Treon SP, Xu L, Yang G, et al. MYD88 L265P mutation in Waldenström’s macroglobulinemia. N Engl
J Med. 2012;367:826-833.
6. Berentsen S. Role of complement in autoimmune hemolytic anemia. Transfus Med Hemother.
2015;42:303-310.
7. Shi J, Rose EL, Singh A, et al. TNT003, an inhibitor of serine protease C1s, prevents complement
activation induced by cold agglutinin disease patient autoantibodies. Blood. 2014;123:4015-4022.
8. Röth A, Bommer M, Hüttmann A, et al. Complement inhibition with eculizumab in patients with
cold agglutinin disease (CAD): results from a prospective phase II trial (DECADE trial). Blood.
2015;101:274.
9. Lyckholm LJ, Edmond MB. Images in clinical medicine: seasonal hemolysis due to cold-agglutinin
syndrome. N Engl J Med. 1996;334:437.
10. Ulvestad E, Berentsen S, Mollnes TE. Acute phase haemolysis in chronic cold agglutinin disease.
Scand J Immunol. 2001;54:249-252.
11. Berentsen S, Ulvestad E, Gjertsen BT, et al. Rituximab for primary chronic cold agglutinin disease: a
prospective study of 37 courses of therapy in 27 patients. Blood. 2004;103:2925-2928.
12. Schöllkopf C, Kjeldsen L, Bjerrum OW, et al. Rituximab in chronic cold agglutinin disease: a
prosepctive study of 20 patients. Leuk Lymphoma. 2006,47:253-260.
13. Barcellini W. Immune hemolysis: diagnosis and treatment recommendations. Semin Hematol.
2015;52:304-312.
14. Berentsen S, Randen U, Vågan AM, et al. High response rate and durable remissions following
fludarabine and rituximab combination therapy for chronic cold agglutinin disease. Blood.
2010;116:3180-3184.
15. Gueli A, Gottardi D, Hu H, et al. Efficacy of rituximab-bendamustine in cold agglutinin haemolytic
anaemia refractory to previous chemo-immunotherapy: a case report. Blood Transfus.
2013;11:311-314.
Seven atom bomb scientists look over a roengenometer at the site of the test atom bomb
explosion on Sept. 13, 1945. Pictured (L to R): Dr. Kenneth T. Bainbridge; Dr. Joseph G.
Hoffmann; Dr. J. Robert Oppenheimer; Dr. Louis H. Hempelmann; Dr. Victor Weisskoff; Dr.
Robert F. Bacher; and Dr. Richard W. Dooson. (AP Photo)
Fliedner received many honors for his scientific contributions and leadership role in
Europe. He was a man of vision and charisma, highly respected in the international
scientific community. His evangelical attitude and passion for research quite probably
reflected the missionary work of his forbearers, who were famous and highly regarded
Lutheran clergyman. Many people who knew him superficially saw him as stern and
uncompromising. But this was not his real character. During the 1968 student protests
in Germany, he arrived at the University seminar room one morning to find students
and technicians sitting on the conference table. When he politely inquired why, they
said they were protesting. He asked, “Protesting what?” They said they weren’t really
sure. He laughed: “Okay, I agree. Now let’s get back to work.”
Ted Fliedner’s death marks the end of a fascinating era in experimental and clinical
hematology. The atomic hematologists gave us many important insights into
hematopoiesis, drugs such as molecularly cloned hematopoietic growth factors, and
clinical techniques such as protected environments and hematopoietic cell transplants.
a. The bikini bathing suit, designed by French engineer Louis Réard, is named for the Bikini Atoll.
The suit was introduced to the public 4 days after the 1st A-bomb test was announced. At that time,
attractive women were called bombshells, and a competing swimsuit designed by Jaques Heim was
called the Atome.
b. Beer drinkers (we are told), in contrast to wine drinkers, want every glass of beer to taste the same.
However, yeast used to ferment the grains continually mutate, potentially changing the beer’s taste.
Schwartz, a chemist, developed a process to remove mutant yeast, which he saved. Because these
yeast contain large amounts of Dann, there was plenty of thymidine available to label with 3H.
c. More on this in the 1989 movie Fat Man and Little Boy and The Making of the Atomic Bomb by
Richard Rhodes.
d. For more on ASH's oral histories, visit www.hematology.org/About/History/4207.aspx.
Dr. Gale and Dr. Hoelzer indicated no relevant conflicts of interest.
The Hematologist:
ASH NEWS AND REPORTS
5
M I N I
R E V I E W
Decoding Tumor Zip Codes to Design Targeted Drugs to Treat Leukemia, Lymphoma, and Solid Tumors
VIRGINIA J. YAO, PhD, 1 MARINA CARDÓ-VILA, PhD, 2 ROSSTIN AHMADIAN, BS, 3 ALA EBAID, MD, 4 WADIH ARAP, MD, PhD, 5 RENATA PASQUALINI, PhD 6
1. Associate Scientist, University of New Mexico Comprehensive Cancer Center; Division of Molecular Medicine, Department of Internal Medicine, University of New Mexico School of Medicine; Albuquerque, NM
2. Research Assistant Professor; Director, Cell and Protein Targeting Core, University of New Mexico Comprehensive Cancer Center; Division of Molecular Medicine, Department of Internal Medicine, University of New Mexico School
of Medicine, Albuquerque, NM
3. Research Technician, University of New Mexico Comprehensive Cancer Center; Division of Molecular Medicine, Department of Internal Medicine, University of New Mexico School of Medicine, Albuquerque, NM
4. Adult Inpatient Medicine Service, Presbyterian Hospital; University of New Mexico Comprehensive Cancer Center; Albuquerque, NM
5. Victor and Ruby Hansen Surface Endowed Chair in Cancer Medicine, Deputy Cancer Center Director, University of New Mexico Comprehensive Cancer Center; Chief, Division of Hematology/Oncology, Department of Internal
Medicine, University of New Mexico School of Medicine; Albuquerque, NM
6. Professor of Internal Medicine, Maralyn S. Budke Endowed Chair in Cancer Experimental Therapeutics; Associate Director, Translational Research, University of New Mexico Comprehensive Cancer Center; Division of Molecular
Medicine, Department of Internal Medicine, University of New Mexico School of Medicine; Albuquerque, NM
Angiogenesis, the
formation of new
blood vessels,
is an essential
physiological
process for
wound healing,
reproduction,
and development.
In cancer,
angiogenesis
is crucial to sustain solid tumor growth and correlates
with metastases. Studies of bone marrow biopsies from
children with leukemia indicate that leukemic cells induce
angiogenesis in the bone marrow.1 The central role of
angiogenesis in cancer promoted the hypothesis that cancer
may be treated with anti-angiogenic drugs. Moreover, other
studies2 proposed that endothelial cells of tumor blood
vessels within specific tumors express unique receptors, or
zip codes, such that targeted delivery of anti-cancer drugs
might be feasible and, simultaneously, could minimize
collateral damage of healthy cells.
To map the molecular heterogeneity within the human
vasculature, a combinatorial peptide bacteriophage library
was screened by in vivo phage display of normal and tumor
blood vessels in cancer patients undergoing terminal
wean.3,4 The phage are engineered to display a short peptide
sequence as a fusion protein on the pIII coat protein, and
phage libraries typically have a peptide diversity of 109.
Importantly, intravenously injected phage extravasate from
leaky tumor blood vessels in vivo to
bind to receptor proteins present
Figure
on the surface of tumor cells, as
well as the extracellular matrix and
perivascular cells. In addition to in
vivo phage display, an in vitro phage
display method, Biopanning and
Rapid Analysis of Selective Interactive
Ligands (BRASIL), was developed and
used to profile the expression of cell
surface receptors of cultured human
cancer cells in the NCI-60 panel (a
National Cancer Institute panel of 60
human cancer cell lines from different
histologic origins and grades).5,6
Recovered phage display peptide
sequences that act as ligands to bind
to accessible receptors expressed
on the luminal surface of endothelial
cells or on the surface of tumor cells.
The experimental design enriches
for phage that bind to accessible
receptors and are internalized upon
receptor binding.
overexpression was also confirmed in breast cancer,9
osteosarcoma,10 and prostate cancer metastases.11
High levels of IL-11Rα in prostate cancer metastases
indicated IL-11Rα might also be expressed in the bone
marrow in leukemia and lymphoma patients.12 Indeed,
this was confirmed by immunohistochemistry and flow
cytometry in all of the leukemia, myeloma, and lymphoma
cell lines tested — MOLT-4, OCI-AML3, K562, KMB7,
THP-1, HL-60, CCRF-CEM, TF-1, SR-786, TUR, RPMI-8226,
and U937. Additionally, IL-11Rα was detected in patientderived bone marrow samples, including acute myeloid
leukemia (AML; n=33), myelodysplastic syndrome (n=4),
myeloproliferative syndrome (n=2), and B-cell malignancies
(n=4). Myelodysplastic syndrome bone marrow specimens
showed focal disease involvement, whereas other cases
showed significant disease involvement ranging from 40 to
60 percent.
A ligand-directed drug candidate, bone metastasis targeting
peptidomimetic-11 (BMTP-11), was developed; it consists
of the CGRRAGGSC peptide fused to the antibacterial
apoptotic peptide, D(KLAKKLAK)2 through a glycinylglycine
linker. D(KLAKKLAK)2 disrupts mitochondrial membranes
and is toxic to eukaryotic cells upon cell internalization.
We hypothesized that the targeting peptide would guide
the apoptotic peptide to the target site and, upon cellular
internalization, lead to cell death in tumor cells that
express IL-11Rα. Following preclinical studies (http://
newdrugapprovals.org/2014/02/28/the-fdas-drug-review-processensuring-drugs-are-safe-and-effective/), a first-in-man phase 0
Other cancer-specific signatures have also been discovered
and characterized. For example, screening human leukemia
and lymphoma cell lines and patient-derived AML and
acute lymphoblastic leukemia (ALL) bone marrow using
a subtractive cell-targeting technology identified a cellinternalizing peptide motif, Phe-Phe/Tyr-X-Leu-Arg-Ser
(FF/YXLRS), where X is any amino acid residue.13 Further
analyses revealed that FF/YXLRS binds to the neuropilin-1
(NRP-1) receptor. Treatment of cultured MOLT-4, CCRFCEM, OCI-AML3, HL-60, K562, SR-786, U937, or RPMI-8226
cells with the NRP-1 targeting peptide, CGFYWLRSC, fused
to D(KLAKKLAK)2 decreased cell viability in the 5- to 30-µm
range. Analyses of bone marrow samples from AML and ALL
patients confirmed NRP-1 expression compared to normal
bone marrow. These data, together with the promising
results of BMTP-11 in targeting prostate cancer metastases
and the improved efficacy of the myristoylated BMTP11 analog against leukemia and lymphoma cells indicate
that tumor-specific molecular zip codes exist and can be
effectively exploited to design drugs to systemically treat
cancers (Figure).
1. Perez-Atayde AR, Sallan SE, Tedrow U, et al. Spectrum of
tumor angiogenesis in the bone marrow of children with acute
lymphoblastic leukemia. Am J Pathol. 1997;150:815-821.
2. Arap W, Pasqualini R, Ruoslahti E. Cancer treatment by targeted
drug delivery to tumor vasculature in a mouse model. Science.
1998;279:377-380.
3. Arap W, Kolonin MG, Trepel M, et al. Steps toward mapping the
human vasculature by phage display. Nat Med. 2002;8:121-127.
4. Staquicini FI, Cardó-Vila M, Kolonin MG, et al. Vascular ligandreceptor mapping by direct combinatorial selection in cancer
patients. Proc Natl Acad Sci U S A.
2011;108:18637-18642.
5. G
iordano RJ, Cardó-Vila M, Lahdenranta
J, et al. Biopanning and rapid analysis of
selective interactive ligands. Nat Med.
2001;7:1249-1253.
6. K
olonin MG, Bover L, Sun J, et al. Liganddirected surface profiling of human cancer
cells with combinatorial peptide libraries.
Cancer Res. 2006;66:34-40.
7. C
ardó-Vila M, Zurita AJ, Giordano RJ, et
al. A ligand peptide motif selected from
a cancer patient is a receptor-interacting
site within human interleukin-11. PLoS
One. 2008;3:e3452.
8. Z
urita AJ, Troncoso P, Cardó-Vila M, et
al. Combinatorial screenings in patients:
the interleukin-11 receptor alpha as a
candidate target in the progression of
human prostate cancer. Cancer Res.
2004;64:435-439.
9. H
anavadi S, Martin TA, Watkins G, et
al. Expression of interleukin 11 and its
receptor and their prognostic value in
human breast cancer. Ann Surg Oncol.
2006;13:802-808.
10. Lewis VO, Ozawa MG, Deavers MT, et
al. The interleukin-11 receptor alpha
as a candidate ligand-directed target
in osteosarcoma: consistent data from
cell lines, orthotopic models, and
human tumor samples. Cancer Res.
2009;69:1995-1999.
In vivo phage display studies
facilitated construction of a human
vascular map from phage that
specifically bind to receptors
11. Pasqualini R, Millikan RE, Christianson
expressed on the vascular beds of
DR, et al. Targeting the interleukin-11
numerous organs or tumor cells.
receptor alpha in metastatic prostate
Schematic of drug development pipeline. Phage display in humans or with cultured tumor cells identified
As expected, various receptors
cancer: a first-in-man study. Cancer.
common and/or unique receptors that can be exploited for targeted drug delivery. In the case of BMTP-11 or
2015;121:2411-2421.
that are uniquely expressed on the
myristoylated BMTP-11, the targeting peptide ligand, CGRRAGGSC, was synthetically fused to the apoptotic
peptide, D(KLAKKLAK)2, and validated in vivo and in vitro, respectively. BMTP-11 was advanced to preclinical
vascular beds in specific tumors
12. Karjalainen K, Jaalouk DE, Bueso-Ramos C,
studies, and following FDA approval, BMTP-11 was tested as a new investigational drug in a first-in-man clinical trial.
et al. Targeting IL11 receptor in leukemia
were identified, as were receptors
and lymphoma: a functional ligandthat are present on the extracellular
directed study and hematopathology
matrix, perivascular cells, and tumor
analysis of patient-derived specimens.
cells. Surprisingly, several common receptors expressed in
clinical trial of BMTP-11 in castrate-resistant prostate cancer
Clin Cancer Res. 2015;21:3041-3051.
different tumor cell types were also identified. For instance,
patients with osteoblastic bone metastasis (NCT00872157)
13. Karjalainen K, Jaalouk DE, Bueso-Ramos CE, et al. Targeting
the National Center for Biotechnology Information Basic
confirmed selective BMTP-11 localization and apoptosis
neuropilin-1 in human leukemia and lymphoma. Blood.
2011;117:920-927.
Local Alignment Search Tool (BLAST) recognized one
induction in tumors in the bone marrow.11 In vitro studies
such peptide, GRRAGGS, to be identical to a short peptide
showed that BMTP-11 preferentially induces cell death in
sequence within interleukin 11 (IL-11).3,7 Subsequent in
MOLT-4 leukemia cells compared with normal white blood
Drs. Arap and Pasqualini have ownership interest (including
vitro and in vivo analyses identified the IL-11 receptor alpha
cells.12 Interestingly, the myristoylated BMTP-11 analog
IP licensing, royalty payments, and prior equity interest) in
(IL-11Rα) as the cognate binding partner. In fact, high levels
increased cell death by ninefold in cultured OCI-AML3, K562,
Arrowhead Research Corp., which is subjected to certain
of IL-11Rα expression in tissue sections from prostate cancer
and MOLT-4 cells compared to the efficacy of the parental
limitations and restrictions under University policy.
8
patients correlated with disease progression. IL-11Rα
BMTP-11 in MOLT-4 cells in the same time frame.
6
The Hematologist:
ASH NEWS AND REPORTS
T H E
H E A D L I N E S
F R O M
H E M A T O L O G I S T
A D V O C A T E
Washington
President Obama Unveils 2017 Budget Proposal and
Announces New “Moonshot” Initiative to End Cancer;
Continued Advocacy by Hematologists Needed to Protect
Funding for NIH
Congressional leaders are in the midst of planning for the annual spending bills, including
federal funding for the National Institutes of Health (NIH). The process formally began with
the Administration’s budget proposal, which was released on February 9.
Prior to the release of his budget request, in his final State of the Union address, President
Barack Obama announced a new nationwide “moonshot” effort led by Vice President Joe
Biden to eradicate cancer. Following the president’s announcement, the vice president
noted that “the goal of this initiative – this “moonshot” – is to seize this moment, to
accelerate our efforts to progress towards a cure, and to unleash new discoveries
and breakthroughs for other deadly diseases.” ASH looks forward to working with the
Administration, Congress, the National Institutes of Health (NIH), as well as the Food and
Drug Administration (FDA) as this new initiative continues to take shape.
To help launch the initiative and build upon the $2 billion increase in funding provided
to NIH in the final fiscal year (FY) 2016 budget passed by Congress in December 2015, the
president’s FY 2017 budget proposal seeks to provide a $33.1 billion investment for the NIH.
The president’s proposed budget also seeks $5.1 billion for the FDA, and $7 billion for the
Centers for Disease Control and Prevention.
It is important to remember that the president’s nonbinding budget proposal merely sets
forth the administration’s priorities and is just one step in a lengthy federal budget process.
In the coming weeks, administration representatives will be called to testify before Congress
on the President’s proposals, and the House and Senate Appropriations Committees will
begin drafting legislation establishing actual federal spending levels for FY 2017.
Though NIH received a substantial increase in funding for the current fiscal year, lawmakers
must understand the need for continued funding for NIH and biomedical research and the
impact that unpredictable funding has on research and patients. Grassroots support is
critical in order to have a voice in the congressional budget process to ensure that the NIH
continues to receive the broad bipartisan support it has received. Members of the ASH
Committee on Government Affairs will be in Washington in March to meet with Members
of Congress and advocate in support of increased funding for biomedical research, but the
Society needs the help of all of its members in continuing to focus attention on this and
other issues of importance to hematology. Please look for ASH Legislative Alerts and visit
the ASH website for updates on the FY 2017 budget process and for information about how
you can contact your senators and representative to protect NIH funding in FY 2017.
For additional information on how to join the ASH Grassroots Network and participate in the
Society’s advocacy efforts, visit the ASH Advocacy Center at www.hematology.org/advocacy,
or contact ASH Legislative Affairs Manager Tracy Roades at troades@hematology.org.
ASH Continues Efforts to Pass Oral Parity Legislation in
U.S. States
Oral and patient-administered forms of chemotherapy have become more prevalent and
represent the standard of care for many types of cancers. Despite their convenience,
efficacy, and low rate of side effects, they are covered differently than intravenous drugs,
leaving many patients responsible for unsustainable high monthly co-payments. As noted in
the last “Headlines from Washington,” ASH is continuing efforts to pass legislation to ensure
that cancer patients have equality of access, and equality of insurance coverage, to all
approved anticancer regimens including, but not limited to, oral and intravenous drugs.
• Michigan: As with efforts in other states, ASH continues to work as part of a larger
coalition of patient and provider organizations to seek passage of oral parity legislation
in Michigan. The 2015 to 2016 legislative session will mark the third attempt to pass
oral chemotherapy legislation in Michigan. The bill (SB 625) was officially read-in on
December 1, 2015, and was assigned to the Senate Insurance Committee, where a hearing
was held on the bill in late January 2016.
• Tennessee: In Tennessee, ASH has been working as part of the Tennessee Fair Access to
Cancer Treatment Coalition. In late January, the Cancer Treatment Fairness Act (SB2091/
HB2239) was introduced in both the state Senate and state House.
• A
laska: Legislation was also introduced in Alaska in late January 2016 (Senate Bill 142),
directing health plans in the state that currently cover cancer treatments to apply the
same cost-sharing for oral therapies as those that are administered intravenously or by
injection. A coalition is being established, and ASH will be working with partners in the
state to push the bill through the legislative process.
If you live in one of these states and are interested in working with ASH to help ensure
that your patients have affordable access to oral chemotherapy drugs, please contact
ASH Legislative Advocacy Manager Tracy Roades at troades@hematology.org. ASH also has
active advocacy campaigns on the Society’s website (www.hematology.org/advocacy) that
allow members residing in these states to quickly and easily contact their state elected
officials.
ASH Calls on Congress to Help Address the Burden of
Sickle Cell Disease
ASH is in the midst of a multifaceted initiative to identify the highest priority actions
needed to improve outcomes for individuals with sickle cell disease (SCD) in the United
States and globally and to map a plan to advance these actions in the short and long term.
In 2016, the Society will announce different parts of this initiative through ASH’s “Call to
Action on SCD.” A major component of this campaign is ASH’s congressional strategy to
raise awareness for SCD on Capitol Hill and promote the need for comprehensive SCD
legislation to enhance current federal SCD programs.
On February 9, ASH kicked off the Society’s SCD-focused advocacy activities by co-hosting
a congressional staff roundtable meeting on SCD with the Sickle Cell Disease Association
of America. The program featured ASH President Dr. Charles Abrams and ASH Vice
President Dr. Alexis Thompson, as well as a sickle cell patient advocate, Mr. Kyle Smith,
who presented startling facts about SCD and the burden of the disease. He also highlighted
new practice-changing guidelines and research and facilitated a discussion of legislative
strategies to help improve the lives of individuals with SCD.
The interactive and educational program was aimed at helping generate congressional
staff interest in SCD and garner support for comprehensive SCD legislation. To continue
the momentum, ASH will continue to work with Members of Congress to introduce SCD
legislation, and the Society will be hosting a second briefing for congressional members and
staff in conjunction with the Committee on Government Affairs’ spring Hill Day on March
23, 2016.
For the latest on ASH’s SCD initiatives and the status of the Society’s related advocacy
efforts, visit www.hematology.org/scd.
ASH has supported legislative efforts at both the federal and state levels and continues to
work with stakeholders and advocacy groups on legislative efforts in numerous states in
2016. Since our last update, there has been significant action on legislation in several states,
as noted below:
• Alabama: 2016 will be the first attempt to pass oral parity legislation in Alabama.
ASH has been working as part of a coalition (the Alabama Cancer Treatment Fairness
Coalition) since early fall 2015 to prepare for the 2016 legislative session. The coalition
has lined up House and Senate sponsors, and as of the publication of this issue of The
Hematologist, plans were to introduce the legislation soon after the start of the session
(which begins in early February and runs through the spring).
ASH’s Officers and a patient advocate participate in the February 9, 2016, Congressional Staff
Roundtable on Sickle Cell Disease. Pictured (L to R): Dr. Kenneth C. Anderson, Dr. Susan B.
Shurin, Dr. Alexis Thompson, Mr. Kyle Smith, Dr. Charles S. Abrams, and Dr. Stephanie J. Lee.
The Hematologist:
ASH NEWS AND REPORTS
7
A Clearer View of HSCs
Acar M, Kocherlakota, Murphy MM, et al. Deep imaging of bone marrow shows non-dividing stem cells are mainly perisinusoidal. Nature. 2015;526:126-130.
D
r. Ray Schofield first hypothesized the concept of a hematopoietic stem cell (HSC) niche
in 1978.1 He proposed that:
The stem cell is seen in association with other cells which determine its behavior…
its maturation is prevented, and as a result, its continued proliferation as a stem cell
is assured. Its progeny, unless they can occupy a similar stem cell “niche,” are first
generation colony-forming cells [progenitors].
This hypothesis implies that stem cells are localized within specific locations in the bone
marrow and that these locations govern the function of stem cells, and in particular, their
proliferation or quiescence. Work ever since, and even before Dr. Schofield’s hypothesis,
has sought to determine the location of HSCs in vivo and to characterize their surrounding
supportive “niche” cells.
Several technological advances throughout the last decade have now allowed for the
visualization of presumed HSCs in tissue and have created numerous different models of the
location and characterization of the HSC niche. Many studies on the hematopoietic niche in
the last decade have relied on antibody staining of phenotypic markers known to enrich for
HSCs, most notably the SLAM family of markers in mice (CD150+, CD48–, CD244–).2 This
earlier report2 of HSC localization using SLAM markers was performed on bone sections from
three femurs. The authors were able to identify 35 total cells, allowing for some speculation
about HSC localization, but a relatively modest number of total events precluded definitive
conclusions.
Later, advances in confocal imaging coupled with phenotypic labeling of HSCs allowed for
live imaging of HSCs in a transplantation scenario.3 These experiments demonstrated that
repopulating HSCs specifically trafficked to, and engrafted near the endosteum in irradiated
mice, suggesting that this endosteal surface was a potential HSC niche location. However,
this early study was also performed with a modest number of events and was limited by the
penetration depth of the imaging. The results also reflected HSCs that were transplanted,
rather than endogenous HSCs at steady state.
A few years ago, an innovative method using whole-mount confocal imaging of the mouse
sternum, coupled with 3D-rendering and computational analysis, demonstrated that quiescent
HSCs were localized near bone marrow arterioles at a much higher rate than at random
locations.4 In contrast to the previously described studies, the authors successfully imaged
hundreds of HSCs in bones per study, and remarkably the same numbers of HSCs were
detected in the whole-mount imaging as by flow cytometry — a significant improvement over
prior studies.
Figure
Before clearing
Before clearing
A new study by Dr. Melih Acar and colleagues has now added to these technological
advances in imaging HSCs in tissue — application of tissue optical clearing and a new
endogenous reporter mouse. Expanding upon whole-mount imaging techniques, the authors
used a tissue-clearing technique previously employed in brain tissues or mouse embryos, to
create “clear” bones (Figure), allowing for deeper penetration of confocal imaging.
Using gene expression profiling from their earlier studies that identified the SLAM markers, 2
the authors also found that α-catulin was highly expressed in HSCs compared with
unfractionated bone marrow cells. A green fluorescent protein (GFP) was then inserted
into the first exon of α-catulin, creating a reporter mouse in which approximately 50
percent of the SLAM cells were GFP+, and there was no detection of GFP in more mature
hematopoietic cells. Coupling GFP expression with antibody staining for c-kit led to similar
enrichment for long-term repopulating HSCs as SLAM markers. Using this two-marker
system and optically cleared sections, the authors used similar spatial analysis to the prior
report4 and demonstrated that these endogenously GFP-labeled c-kit+ cells were contained
more commonly within the central marrow rather than in bone surfaces. Approximately 85
percent of the cells were within 10 μm of a sinusoidal vessel. However, if a similar analysis
was performed by comparing the distance of randomly placed spots in the bone marrow
cavity to sinusoids, there was no statistical difference between the random spots and the
HSCs, due to the abundance of sinusoids in the bone marrow space. Surprisingly, there
was no localization difference observed between cycling versus noncycling HSCs. The
authors also coupled their imaging analysis with CXCL12 reporter mice and Leptin-receptor
reporter mice and demonstrated that the vast majority of HSCs are within 5 μm of these
reporter cells within the marrow niche. While this localization of HSCs was significantly
different than randomly placed spots, 85 to 90 percent of random spots also were within 5
μm of these reporter cells, demonstrating how ubiquitous these cells and “niche” locations
are within the marrow space.
Recently, a number of studies have described numerous cell types that comprise the HSC
niche, largely driven by the availability of a specific Cre-recombinase or related reporter
mouse strain. Consequently, a series of publications have described the “cell identity”
of the HSC niche based on the mouse model including Lepr-Cre, Prx1-Cre, Nestin-Cre,
NG2-Cre, CXCL12-GFP, Mx1-Cre, Osx-Cre, and others. While the field has advanced as
a result of these new mouse models, many of these Cre systems were not conditionally
activated, meaning that the phenotype observed may not faithfully represent what happens
in the adult stem cell niche. Secondly, none of these Cre or reporter systems are restricted
to an exclusive cell type, and there are many known and unknown overlaps. Finally, different
variants of the same reporter system often result in different phenotypes, adding to
uncertainty in niche cell identity.
The next decade of HSC niche research is likely to involve the use of still-emerging
technologies, and our understanding of the niche (specifically what has occurred this past
decade) will become simultaneously clearer and more convoluted. It will be important to
apply these technologies both in steady-state situations as well as in situations of stress
and disease, particularly HSC transplantation. Notably, optical clearing and deep tissue
imaging also has been used by the authors to begin to explore HSC localization in the
spleen (Figure) during extramedullary hematopoiesis.5 As more groups adopt these new
techniques and apply them to their own model systems it is likely that the HSC niche will
continue to be parsed into smaller and smaller subsets of locales and cells, perhaps with
differing regulatory properties.
1. Schofield R. The relationship between spleen colony-forming cells and the haematopoietic stem cell. Blood Cells.
1978;4:7-25.
2. Kiel MJ, Yilmaz OH, Iwashita T, et al. SLAM family receptors distinguish hematopoietic stem and progenitor cells and
reveal endothelial niches for hematopoietic stem cells. Cell. 2005;121:1109-1121.
After clearing
After clearing
3. Lo Celso C, Fleming HE, Wu JW, et al. Live-animal tracking of individual hematopoietic stem/progenitor cells in their
niche. Nature. 2009;457:92-96.
4. Kunisaki Y, Bruns I, Scheiermann C, et al. Arteriolar niches maintain haematopoietic stem cell quiescence. Nature.
2013;502:637-643
5. Inra CN, Zhou BO, Acar M, et al. A perisinusoidal niche for extramedullary haematopoiesis in the spleen. Nature.
2015;527:466-471.
Optical clearing of hematopoietic tissues for
deep imaging. Shown are representative images of
a mouse femur (left) or spleen (right) before and after
the application of tissue optical clearing.
JONATHAN HOGGATT, PhD
Dr. Hoggatt indicated no relevant conflicts of interest.
8
The Hematologist:
ASH NEWS AND REPORTS
Short-Term Treatment Strategies for
Recurrent Venous Thromboembolism
Mutated Calreticulin Stimulates the Thrombopoietin Receptor
to Drive the Development of MPN
Schulman S, Zondag M, Linkins L, et al. Recurrent venous
thromboembolism in anticoagulated patients with cancer:
management and short-term prognosis. J Thromb Haemost.
2015;13:1010-1018.
Chachoua I, Pecquet C, El-Khoury M, et al. Thrombopoietin receptor activation by myeloproliferative
neoplasm associated calreticulin mutants. Blood. 10.1182/blood-2015-11-681932 [Epub ahead of print].
E
ven with optimal anticoagulant therapy, as many as 8
percent of cancer patients experience recurrent venous
thromboembolism (VTE) within six months of their index
event.1 Unfortunately, there is no high-quality evidence to
guide the management of anticoagulation failure in such patients.
Using an observational study design, Dr. Sam Schulman and
colleagues provide us with more information about how cancer
patients are treated after a breakthrough VTE, and how frequently
various anticoagulation strategies are associated with outcomes
such as (second) recurrent VTE and major bleeding.
The authors included data on 212 patients who both had
cancer and experienced VTE despite anticoagulant therapy.
Data from approximately one-third of the patients were gathered
retrospectively; the other two-thirds of included patients were
studied in a prospective fashion. During the three months after
their breakthrough event, the treatment used for each patient
was recorded, and all patients were followed for VTE events,
major bleeding, residual thrombosis symptoms, and death. Event
rates associated with the different treatment strategies were
compared using Cox proportional hazards regression. Within this
cohort of patients who had failed some sort of anticoagulant,
59 percent had adenocarcinoma and 73 percent had known
metastases. When they experienced their breakthrough event,
70 percent of patients were using low-molecular-weight heparin
(LMWH), while 27 percent were on a vitamin K antagonist
(VKA). While insufficiently aggressive anticoagulation probably
explained at least some of the treatment failures, 70 percent of
included patients were known to be receiving a therapeutic or
supratherapeutic dose at the time they experienced a qualifying
event. The treatment used by the local physician after the index
event was unchanged anticoagulant (and unchanged, therapeutic
dose) in 33 percent, unchanged anticoagulant (but dose
increased) in 31 percent, and a different anticoagulant in 24
percent (most of these patients switched from VKA to LMWH).
During the subsequent three months, 8 percent had major
bleeding, 11 percent had another VTE, and 27 percent died.
Additional VTE recurrence was less common with LMWH than
with a VKA (hazard ratio [HR], 0.28; 95% confidence interval
[CI], 0.11-0.70) but was similar with unchanged or increased
anticoagulant intensity (HR, 1.09; 95% CI, 0.45-2.63).
Although the observational nature of this study is limited by the
authors’ inability to adjust for potential confounding variables,
Dr. Schulman and colleagues have provided important, new
information that may help both clinicians and investigators
charged with defining the management of cancer patients
who experience VTE recurrence despite anticoagulation. First,
anticoagulation failure in cancer patients is associated with
a guarded prognosis: More than one quarter of the persons
included in this registry died within three months of their
breakthrough event. Second, the present findings support the
widespread practice of switching to LMWH when a cancer
(or other) patient has recurrent thrombosis while taking VKA.
Unfortunately, clinicians are still left without definitive evidence
about how best to treat the cancer patient who experiences
new VTE while on LMWH. Many physicians recommend
increasing the LMWH dose (by 20%-30%) in this situation, and,
the possibility of selection bias notwithstanding, the findings
of Dr. Schulman and colleagues suggest that increasing the
dose of LMWH is not prohibitively risky. On the other hand,
the observational nature and small size of this registry leave us
uncertain about whether (or to what extent) this dose escalation
strategy is beneficial.
Elf S, Abdelfattah N, Chen E, et al. Physical interaction between mutant calreticulin and the
thrombopoietin receptor is required for hematopoietic transformation. Blood. 2015;126:LBA-4.
T
he major BCR-ABL1–negative myeloproliferative neoplasms (MPNs) include polycythemia vera (PV),
essential thrombocythemia (ET), and primary myelofibrosis (PMF). These chronic myeloid malignancies
are caused by constitutive activation of the JAK-STAT pathway producing elevated blood counts, most
often through JAK2 V617F mutations.1 Mutations in the thrombopoietin receptor (TpoR/MPL) are also
found in patients with ET and PMF.2 In 2013, mutations in exon 9 of the C-terminal domain of the calreticulin
(CALR) gene were identified in a significant subset of ET and PMF, but not PV.3,4 The mutations uniformly
result in a 1-base pair (bp) frameshift which in turn leads to loss of the endoplasmic reticulum retention
sequence, or KDEL. Two major subtypes of CALR mutations have been identified, which account for the vast
majority of mutations. The 52 bp deletion ([del52]; type 1) is more commonly associated with myelofibrosis
than the 5 bp insertion ([ins5]; type 2).5,6 The mechanism by which CALR mutations lead a MPN phenotype
has puzzled investigators since their discovery.
To examine the role of CALR and its interactions with cytokine receptors, Drs. Ilyas Chachoua and Stephan
Constantinescu and colleagues employed retroviruses to infect cell lines with mutant CALR. The cytokinedependent BaF3 cell line was infected with retroviral plasmid containing CALR wild-type, del52, or ins5
sequences, as well as one of several cytokine receptors including MPL, the EPO receptor (EpoR), and G-CSF
receptor (GCSFR). These cells were induced to have autonomous growth with mutant CALR and MPL, and,
to a limited extent, GCSFR. These findings showed that mutant CALR requires MPL and does not interact
with EpoR.
To explore the role of JAK2 in MPL activation, the JAK2-deficient γ-2a cell line was used. These cells could
not induce MPL activation in the presence of mutant CALR, indicating the requirement of JAK2. Further
emphasizing this point, the JAK2 inhibitor ruxolitinib was successful in inhibiting proliferation of Ba/F3 cells
with mutant CALR. Interestingly, the addition of a MEK-ERK inhibitor, but not a PI3-K inhibitor, provided a
synergistic effect.
Alteration of MPL N-glycosylation sites blocked mutant CALR from activating MPL. This activation was
independent of Tpo, as demonstrated by Tpo-binding deficient MPL, which could still be activated by mutant
CALR. The authors hypothesize that CALR mutants may stabilize one of the active interfaces of MPL in
addition to directly interacting with MPL. This could explain why CALR mutants do not interact with other
N-glycosylated mutated receptors, and why the del52 and ins5 have different clinical phenotypes. Finally, this
group verified the importance of the MPL/JAK2 signaling pathway in primary cells from CALR-mutated ET
patients. Short hairpin RNAs targeting MPL or JAK2 were successful in inhibiting Tpo-independent colony
formation.
Similar findings were presented at the 2015 ASH annual meeting by Dr. Shannon Elf and colleagues from
the laboratory of Dr. Ann Mullally. By overexpressing CALR-del52 in the cytokine dependent BaF3 cell line,
IL-3 independent growth was achieved in cells expressing MPL, but not in cells expressing EpoR. These
cells exhibited increased phosphorylation of MPL, JAK2, and STAT3, and the JAK1/JAK2 inhibitor ruxolitinib
could block STAT3 activation in a phospho-flow cytometry assay. A variety of mutant CALR proteins were
studied, and it was found that the positive charge of the C-terminus was critical for its transforming capacity.
This mutant CALR physically interacts with MPL, as shown by co-immunoprecipitation. These findings are in
agreement with Dr. Chachoua and colleagues by showing that mutant CALR interacts with MPL and signals
through the JAK-STAT pathway.
This research provides important insights into the pathophysiology for CALR-mutated MPN and proposes an
intriguing mechanism of a mutated chaperone protein inducing cytokine activation. These findings suggest
a novel signaling paradigm whereby a mutated CALR undergoes a different cellular localization from the
wild-type protein and induces activation of MPL at the N-glycosylation site through JAK2, independent of Tpo.
The observation that different mutations in CALR may stabilize different active interfaces of MPL provides
a possible explanation for different clinical phenotypes. Importantly, by demonstrating a JAK-STAT signaling
pathway that is different from the JAK2 V617F driven neoplasms, these data offer hope for new therapeutic
opportunities (Figure; available online only).
1. Cazzola M, Kralovics R. From Janus kinase 2 to calreticulin: the clinically relevant genomic landscape of myeloproliferative neoplasms. Blood.
2014;123:3714-3719.
2. Vainchenker W, Delhommeau F, Constantinescu SN, et al. New mutations and pathogenesis of myeloproliferative neoplasms. Blood.
2011;118:1723-1735.
3. Klampfl T, Gisslinger H, Harutyunyan AS, et al. Somatic mutations of calreticulin in myeloproliferative neoplasms. N Engl J Med.
2013;369:2379-2390.
4. Nangalia J, Massie CE, Baxter EJ, et al. Somatic CALR mutations in myeloproliferative neoplasms with nonmutated JAK2. N Engl J Med.
2013;369:2391-2405.
5. Cabagnols X, Defour JP, Ugo V, et al. Differential association of calreticulin type 1 and type 2 mutations with myelofibrosis and essential
thrombocythemia: relevance for disease evolution. Leukemia. 2015;29:249-252.
6. Pietra D, Rumi E, Ferretti VV, et al. Differential clinical effects of different mutation types in CALR-mutant myeloproliferative neoplasms.
Leukemia. 2015; doi:10.1038/leu.2015.277. [Epub ahead of print].
1. Lee AY, Levine MN, Baker RI, et al. Low-molecular-weight heparin versus a
coumarin for the prevention of recurrent venous thromboembolism in patients with
cancer. N Engl J Med. 2003;349:146-153.
DAVID A. GARCIA, MD
DAVID T. LYNCH, MD, TRACY I. GEORGE, MD
Dr. Garcia indicated no relevant conflicts of interest.
Dr. Lynch and Dr. George indicated no relevant conflicts of interest.
The Hematologist:
ASH NEWS AND REPORTS
9
What Lies Beneath? Prevalence of Heritable
Mutations in Pediatric Cancer
One Step Closer to Functionally Characterizing the
Human Genome: Genomic Screens Identify Essential
Genes and Liabilities in Cancer Cells
Zhang J, Walsh MF, Wu G, et al. Germline mutations in predisposition
genes in pediatric cancer. N Engl J Med. 2015;373:2336-2346.
Wang T, Birsoy K, Hughes NW, et al. Identification and characterization of essential genes
in the human genome. Science. 2015;350:1096-1101.
I
M
n 1971, Dr. Alfred G. Knudson proposed his “two-hit” hypothesis to explain
the role of recessive tumor suppressor genes in dominantly inherited
cancer syndromes. He postulated that the first hit was inherited, and the
second hit was acquired and triggered tumorigenesis.1 This hypothesis
was subsequently confirmed by the demonstration of a loss of heterozygosity
at 13q14 in retinoblastomas2 and the cloning of the first tumor suppressor
gene RB1.3 Since then, numerous genes associated with inherited cancer
predisposition syndromes have been discovered. Mutations in these genes lead
to disease through several mechanisms, including, but not limited to, inactivation
of tumor suppressor genes. The frequency of germline mutations in cancerpredisposition genes in children and adolescent patients had formerly not been
determined across a broad range of tumor types.
To determine this frequency, Dr. Jinghui Zhang and colleagues performed wholegenome and/or whole-exome sequencing of constitutional DNA purified from
blood samples from 1,120 children with a variety of cancers. The median age of
the patients was 6.9 years (range, 8 days to 19.7 years). Using a candidate-gene
analysis approach that largely focused on 60 known autosomal-dominant or 29
autosomal-recessive cancer-predisposition genes, they found that 8.5 percent of
the patients (95 of 1,120) harbored pathogenic or likely pathogenic mutations in
their candidate genes compared with 1.1 percent (11 of 966) and 0.6 percent
(4 of 723) in two cancer-free control groups. The most commonly mutated genes
included TP53 (Li-Fraumeni syndrome), APC (familial adenomatous polyposis),
BRCA2 (familial ovarian-breast cancer), NF1 (neurofibromatosis), PMS2
(hereditary colorectal cancer), RB1 (hereditary retinoblastoma), and RUNX1
(congenital thrombocytopenia with predisposition to myelodysplastic syndrome/
acute myeloid leukemia). Among those patients with a monoallelic germline
mutation, 66 percent (61 of 93) harbored a second hit within the tumor genome
as shown by loss of heterozygosity or mutational inactivation of the second allele.
The prevalence of pathogenic or likely pathogenic germline mutations in autosomal
dominant cancer–predisposition genes was highest among patients with non–central nervous system (non-CNS) solid tumors (16.7%; 48/287), followed by those
with CNS tumors (8.6%; 21 of 245). The histologic subtypes of CNS tumor that
were most often associated with germline mutations included choroid plexus carcinoma (25%; 1 of 4), medulloblastoma (13.5%; 5 of 37), high-grade glioma (9.1%;
9 of 99), low-grade glioma (7.9%; 3 of 38), and ependymoma (6.0%; 4 of 67). The
prevalence of germline mutations varied among patients with different subtypes
of non-CNS solid tumors: 69.2 percent for adrenocortical tumor (27 of 39), 17.9
percent for osteosarcoma (7 of 39), 13.3 percent for retinoblastoma (2 of 13),
10.9 percent for Ewing’s sarcoma (5 of 46), 7.0 percent for rhabdomyosarcomas
(3 of 43), and 4.0 percent for neuroblastoma patients (4 of 100). The incidence in
leukemia patients was 4.4 percent (26 of 588). Eight patients harbored germline
mutations in the adult-onset cancer-predisposition genes BRCA1, BRCA2, and
PALPB2. These genes are not typically sequenced in pediatric cancer patients
as they are thought to predispose to adult cancer. Only one of these patients’
tumors exhibited evidence for mutational inactivation or loss of the second allele.
Importantly, the investigators uncovered a family history of a first- or second-degree
relative with cancer in only 40 percent of the 95 patients with a putative heritable
mutation who had charts documenting a family history (18 of 43 records).
The study likely underestimates the proportion of pediatric cancer patients
harboring a heritable cancer-susceptibility mutation as the candidate-gene
approach excluded analysis of most of the genes in the genome. Additionally, our
understanding of mutations in noncoding regions of the genome is limited, and
thus pathogenic mutations in these regions could have been missed.
This is the most comprehensive study to date of the genetics of childhood cancer
predisposition. It demonstrates the clinical utility of next-generation sequencing to
identify inherited cancer predisposition in pediatric and young adult patients. The
quality and depth of sequencing allowed identification of mutations that would
have been missed by standard Sanger sequencing, including the identification
of germline mosaicism. This broad genetic approach to diagnosis highlights how
patients with inherited cancer predisposition may present with atypical findings,
that is, cancers not commonly expected within the phenotypic spectrum of their
disorder and in the absence of a strong family history of cancer. This work also
raises a number of important questions, including whom to test; do BRCA1,
BRCA2, or PALB2 mutations contribute to pediatric cancer; what additional
factors contribute to cancer development; and would the inclusion of more
inherited marrow failure and inherited predisposition to leukemia/myelodyplastic
syndrome genes in the analyses have altered the conclusions. More work is
needed to address these and other questions as we sort out how best to
incorporate germline sequencing into clinical care.
1. Knudson AG Jr. Mutation and cancer: statistical study of retinoblastoma. Proc Natl Acad Sci USA.
1971;68:820-823.
2. Cavenee WK, Hansen MF, Nordenskjold M, et al. Genetic origin of mutations predisposing to
retinoblastoma. Science. 1985;228:501-503.
3. Friend SH, Bernards R, Rogelj S, et al. A human DNA segment with properties of the gene that
predisposes to retinoblastoma and osteosarcoma. Nature. 1986;323:643-646.
4. Holmfeldt L, Wei L, Diaz-Flores E, et al. The genomic landscape of hypodiploid acute lymphoblastic
leukemia. Nat Genet. 2013;45:242-252.
10
ore than 15 years ago, the Human Genome Project provided a comprehensive
sequence of our genome’s gene-containing regions. We now have the ability to
directly edit DNA in a systematic manner using a variety of techniques, allowing the
comprehensive study of the function of all genes.
Three independent studies have recently furthered our understanding of those genes that are
indispensable for the viability of human cells.1-3 One of those studies, by Dr. Tim Wang and
colleagues, utilized a near-haploid human chronic myelogenous leukemia (CML) cell line called
KBM7 (karyotype: 25, XY, +8, Ph+) to disrupt DNA coding sequences throughout the genome and
uncover which genes are essential to the survival of these cells.1 Using a CRISPR/Cas9–based
gene-editing strategy with pools of lentiviruses containing small-guide RNA (sgRNA), they targeted
every protein-coding gene in the genome (Figure A). Comparison of sgRNA abundance between
the initial infected cell population and 14 population doublings then identified those sgRNAs
and the corresponding genes, which were depleted in the final population. In an orthogonal
approach, they also utilized retroviral gene-trap mutagenesis to disrupt the coding sequence
of all protein-coding
genes. Integration
Figure
of a gene-trap in the
sense orientation within
the coding region
of a gene results in
gene inactivation
while integration in
the antisense has no
effect. The proportion
of gene-trap insertions
in the activating versus
inactivating orientation
for each gene in the
genome thereby allows
for deduction of the
genes that have an
essential function. A
similar methodology of
gene-trap insertional
mutagenesis in KBM7
cells and an additional
cell line derived from
KBM7 cells, was
also published by Dr.
Vincent A. Blomen
and colleagues in the
same issue of Science
magazine.2 Finally,
Functional screens to identify essential genes in human cells.
Dr. Traver Hart and
(A) Two approaches taken by Dr. Tim Wang and coauthors to identify genes
colleagues utilized a
essential for human cell survival. One approach utilized CRISPR-mediated
genome-wide CRISPR
gene deletion using pools of small-guide RNAs (sgRNAs) targeting all
negative-selection
protein-coding genes (top). They simultaneously utilized retroviral-mediated
screen across five
insertion of gene traps into the coding sequence of all protein-coding
human cancer cell lines
genes (bottom). (B) Table depicting the cell types used in similar functional
to identify core fitness
genomic screens to identify essential genes in three recent studies.
genes (Figure B).3
The results from each of the three mentioned studies were enlightening and highly analogous in
their findings. First, all three made the surprising finding that approximately 2,000 genes (nearly
10% of the genes in the human genome) are essential. The majority of essential genes have similar
attributes that reflect their critical roles: they are often conserved amongst species, evolve slowly,
rarely have paralogs, are highly expressed, tend to be rich in protein-protein interactions, and
are rarely affected by nonsynonymous mutations. More surprisingly, roughly 300 of the essential
genes in our genome have no previously studied function. The discovery of these newly identified
essential genes was made possible through the systemic use of techniques to directly mutagenize
DNA, identifying fourfold to fivefold more essential genes compared with prior similar efforts using
RNA interference.
While the studies by Dr. Wang and Dr. Hart and their colleagues begin to define genes that appear
to be essential in the context of specific cancer oncogenes (such as BCR-ABL1 and KRAS
G13D), these represent only the beginning of such efforts.1,3 For example, the study by Dr. Blomen
and colleagues revealed that those genes that are nonessential on their own may actually result in
cell death when co-deleted with another nonessential gene.2 Systematic efforts to determine similar
synthetic lethal interactions between pairs of nonessential genes may be especially important in
identifying novel targets for cancer therapy. Indeed, it is estimated that each nonessential human
gene may have approximately 20 synthetic lethal partner genes.2 Moreover, identification of
nonessential genes, which are synthetic lethal in the context of specific cancer drugs, may provide
further therapeutic insights. Future efforts utilizing the techniques, tools, and knockout cells created
in these studies may provide insight into novel functions of our genome and new therapeutic
vulnerabilities to target cancer.
1. Wang T, Birsoy K, Hughes NW, et al. Identification and characterization of essential genes in the human genome. Science.
2015;350:1096-1101.
2. Blomen VA, Majek P, Jae LT, et al. Gene essentiality and synthetic lethality in haploid human cells. Science.
2015;350:1092-1096.
3. Hart T, Chandrashekhar M, Aregger M, et al. High-resolution CRISPR screens reveal fitness genes and genotype-specific
cancer liabilities. Cell. 2015;163:1515-1526.
SIOBAN KEEL, MD
JUSTIN TAYLOR, MD, AND OMAR ABDEL-WAHAB, MD
Dr. Keel indicated no relevant conflicts of interest.
Drs. Taylor and Abdel-Wahab indicated no relevant conflicts of interest.
The Hematologist:
ASH NEWS AND REPORTS
Chimeric Antigen Receptor T Cells for the Treatment of
Multiple Myeloma
Novel Targets in Primary Central Nervous
System Lymphoma
Maus MV, Grupp SA, Porter DL, et al. Antibody-modified T cells: CARs take the front
seat for hematologic malignancies. Blood. 2014;123:2625-2635.
Chapuy B, Roemer MG, Stewart C, et al. Targetable genetic features of
primary testicular and primary central nervous system lymphomas. Blood.
blood-2015-10-673236 [Epub ahead of print].
I
n 2015, the U.S. Food and Drug Administration (FDA) approved four drugs with novel
mechanisms for the treatment of multiple myeloma (MM): panobinostat, daratumumab,
elotuzumab, and ixazomib. The evolving treatment strategies and rapid increase in offerings
are perhaps unmatched in the recent history of drug development for hematologic
malignancies. However, MM remains an incurable malignancy. Novel immunotherapies, such as
chimeric antigen receptor (CAR) T cells, B-cell–specific monoclonal antibodies, and checkpoint
inhibitors, are promising therapies that are helping to advance the field.
As reported by Dr. Marcela V. Maus and colleagues, transduction of autologous T cells to express
CD-19–specific CARs is a promising immunotherapeutic approach for the treatment of B-cell
cancers.1 In a case report published in the New England Journal of Medicine, Dr. Alfred L.
Garfall and colleagues reported the outcome of autologous transplantation followed by treatment
with CTL019 cells, which consist of autologous T cells expressing a CD3-zeta/CD137–based
anti–CD-19 CAR from a lentiviral vector. The approach led to a complete response with no
evidence of progression and no measurable serum or urine monoclonal protein when reported
12 months after treatment of a patient with refractory MM, who had received nine prior lines of
therapy, including lenalidomide, bortezomib, carfilzomib, pomalidomide, vorinostat, clarithromycin,
and elotuzumab.2 CD-19 is infrequently expressed on MM cells and is not generally considered
a strong target. However, this and other reports suggest that there is a minor population of MM
clones with drug-resistant, disease-propagating properties that have a B-cell phenotype (i.e., CD19–positive).3 The efficacy of CAR T cells in this small subset of MM patients begs the question
of whether there is a more MM-specific target to which this strategy may be applied.
B-cell maturation antigen (BCMA; CD269) is a member of the TNF receptor superfamily,
TNFRSF17.4 Expression of BCMA is restricted to the B-cell lineage where it is predominantly
expressed in the interfollicular region of germinal centers5 and on differentiated plasma cells6
and plasmablasts.7 BCMA is virtually absent on naïve and memory B cells8,9 but it is selectively
induced during plasma cell differentiation where it may support humoral immunity by promoting
the survival of normal plasma cells and plasmablasts.
In a late-breaking abstract presented during the 2015 ASH Annual Meeting, Dr. Syed Abbas
Ali and colleagues presented the first in-human clinical trial of T cells expressing anti-BCMA
CAR T cells. Patients had advanced MM with a median of seven prior lines of therapy. Patients
received a single infusion of CAR-BCMA T cells. Prior to CAR T-cell infusion, patients received
300 mg/m2 cyclophosphamide and 30 mg/m2 fludarabine to enhance activity of the CAR T
cells by depleting endogenous leukocytes. Two patients were treated at the highest dose level:
One attained a stringent complete response, and the other had a very good partial response.
Both patients treated at the highest dose level experienced signs of cytokine release syndrome,
including fever, tachycardia, hypotension, hypoxia, and coagulopathy. The toxicities were similar
to those seen in leukemia patients treated with anti–CD-19 CAR T cells. This trial suggests
that there may be strong anti-MM activity for CAR T cells targeting BCMA.
Humanized monoclonal antibodies against BCMA are another area of investigation showing
great promise in the field.10 These and future studies will determine whether off-the-shelf
approaches such as the use of monoclonal antibodies directed against BCMA, versus the
more patient-specific CAR T-cell approaches, will yield better long-term disease control. The
obvious advantage of BCMA-directed monoclonal antibodies is the easy access and potential
lack of toxicity. However, with the use of tocilizumab, a humanized monoclonal antibody directed
against interleukin-6 receptor, to treat CAR T cell–related cytokine release syndrome, and with
better supportive care strategies, cellular therapies may also become better tolerated over time.
L
ymphoma involving the central nervous system (CNS) and the testes has
long posed a therapeutic challenge given the paucity of active systemic
chemotherapy achieving pharmacologic levels in these sanctuary sites.
Since the 1950s, methotrexate has been used as an antineoplastic
drug, and high-dose methotrexate remains the cornerstone of treatment for
CNS lymphoma, although durable remission is extremely rare. As the majority
of patients affected by recurrent primary CNS lymphoma (PCNSL) and primary
testicular lymphoma (PTL) are elderly and not appropriate candidates for highdose chemotherapy with stem cell rescue, novel therapeutic approaches for these
diseases are desperately needed.
Dr. Bjoern Chapuy and colleagues recently performed a comprehensive analysis of
the genetic features of PCNSL (Epstein Barr virus negative) and PTL. By analyzing
copy number alterations, chromosomal rearrangements, and recurrent somatic
mutations, the authors described a genetic signature of the two diseases, clearly
distinct from that of primary mediastinal B-cell lymphoma (PMBL) and diffuse
large B-cell lymphoma (DLBCL; Figure). Their findings establish a basis for clinical
investigation of novel targeted approaches.
Overall, PCNSL and PTL have a unique set of abnormalities characterized by
genomic instability, abnormal signaling through the Toll-like receptor (TLR) —
often in combination with activation of the B-cell receptor (BCR) pathway, and
upregulation of programed cell death-1 (PD-1) ligands. Unlike DLBCL, in which
p53 and related cell cycle proteins are dysregulated, frequent copy number
alterations were found, including bi-allelic loss of CDKN2A, which lies upstream
of p53. In terms of mutations, nearly all cases of both PCNSL and PTL harbored
MYD88 L265P mutations. MYD88 is a protein used by TLRs to activate transcription
through NF-κB. This mutation is found in the vast majority of cases of Waldenström
macroglobulinemia and in approximately 30 percent of the activated B-cell subtype
of DLBCL. Copy gains of NFKBIZ, which also regulates NF-κB signaling, were
frequently identified, as were alterations in the B-cell receptor component CD79B.
Lastly, copy gains of 9p24.1, which includes the genes for programmed deathligands 1 and 2 (PDL1 and PDL2) were found in more than 50 percent of cases of
PCNSL and PTL.
These findings provide insight into oncogenic pathways in primary CNS lymphoma
and primary testicular lymphoma that are unique compared with other subtypes of
DLBCL. PD-1 inhibitors are actively being studied in Hodgkin lymphoma as well as
multiple subtypes of non-Hodgkin lymphoma. Studies in other tumor types suggest
that these drugs have activity in primary and secondary tumors involving the CNS,
including melanoma and glioblastoma. Therefore, evaluation of these agents in
PCNSL and PTL is warranted. Additionally, IMO-8400, an antagonist to TLR 7, 8,
and 9, is currently being evaluated in MYD88L265P-mutated DLBCL. Whether these
agents will have activity in PCNSL and PTL is yet to be determined, but rational
approaches based on this work provide hope for improving treatment beyond highdose chemotherapy.
Figure
Additional immune strategies are currently under investigation. For example, checkpoint inhibitors such as pembrolizumab, a humanized monoclonal antibody of the IgG4/κ isotype against the
programmed cell death 1 receptor, showed very promising results in combination with both lenalidomide and pomalidomide, and dexamethasone in heavily pretreated populations.11,12 Similarly,
the overall response rate (ORR) for patients receiving pembrolizumab, lenalidomide, and dexamethasone was 76 percent in a heavily pretreated population (median, four prior lines of therapy);
among the lenalidomide-refractory patients, the ORR was 56 percent. In a year of unparalleled
drug development, there is even more optimism to embrace as we begin to harness the power of
the immune system to treat relapsed disease with an eye on the ultimate goal of curing MM.
1. Maus MV, Grupp SA, Porter DL, et al. Antibody-modified T cells: CARs take the front seat for hematologic malignancies.
Blood. 2014;123:2625-2635.
2. Garfall AL, Maus MV, Hwang WT, et al. Chimeric antigen receptor T cells against CD19 for multiple myeloma. N Engl J
Med. 2015;373:1040-1047.
3. Hajek R, Okubote SA, Svachova H, et al. Myeloma stem cell concepts, heterogeneity and plasticity of multiple myeloma.
Br J Haematol. 2013;163:551-564.
4. Ryan MC, Hering M, Peckham D, et al. Antibody targeting of B-cell maturation antigen on malignant plasma cells. Mol
Cancer Ther. 2007;6:3009-3018.
5. Chiu A, Xu W, He B, et al. Hodgkin lymphoma cells express TACI and BCMA receptors and generate survival and
proliferation signals in response to BAFF and APRIL. Blood. 2007;109:729-739.
6. O’Connor BP, Raman VS, Erickson LD, et al. BCMA is essential for the survival of long-lived bone marrow plasma cells. J
Exp Med. 2004;199:91-98.
7. Avery DT, Kalled SL, Ellyard JI, et al. BAFF selectively enhances the survival of plasmablasts generated from human
memory B cells. J Clin Invest. 2003;112:286-297.
8. Novak AJ, Darce JR, Arendt BK, et al. Expression of BCMA, TACI, and BAFF-R in multiple myeloma: a mechanism for
growth and survival. Blood. 2004;103:689-694.
9. Jelinek DF, Darce JR. Human B lymphocyte malignancies: exploitation of BLyS and APRIL and their receptors. Curr Dir
Autoimmun. 2005;8:266-288.
10.Tai YT, Mayes PA, Acharya C, et al. Novel anti-B-cell maturation antigen antibody-drug conjugate (GSK2857916)
selectively induces killing of multiple myeloma. Blood. 2014;123:3128-3138.
Unique combinations of structure alterations in discrete LBCL subtypes. The
table notes frequency of specific genetic alterations modulating “genomic instability,”
“oncogenic TLR and BCR signaling,” and “PD-1 ligand deregulation” in all DLBCL,
ABC-type DLBCL, PTL, EBV PCNSL, and PMBL. Used with permission.
11.San Miguel J, Mateos MV, Shah JJ, et al. Pembrolizumab in combination with lenalidomide and low-dose dexamethasone
for relapsed/refractory multiple myeloma: keynote-023. Blood. 2015;126:505.
12.Badros AZ, Kocoglu MH, Ma N, et al. A phase II study of Anti PD-1 antibody pembrolizumab, pomalidomide, and
dexamethasone for relapsed/refractory multiple myeloma. Blood. 2015;126:506.
ELIZABETH K. O’DONNELL, MD, AND NOOPUR S. RAJE, MD
ANN S. LACASCE, MD
Drs. O'Donnell and Raje indicated no relevant conflicts of interest.
Dr. LaCasce indicated no relevant conflicts of interest.
The Hematologist:
ASH NEWS AND REPORTS
11
Antithymocyte Globulin Proves a
Promising Ally against GVHD
Expanding the Mutational Spectrum in Juvenile Myelomonocytic
Leukemia
Kröger N, Solano C, Wolschke C, et al. Antilymphocyte
globulin for prevention of chronic graft-versus-host
disease. N Engl J Med. 2016;374:43-53.
Stieglitz E, Taylor-Weiner AN, Chang TY, et al. The genomic landscape of juvenile myelomonocytic leukemia.
Nat Genet. 2015;47:1326-1333.
The major outcome of the study is that the incidence of
chronic GVHD was more than halved, from 68.7 percent
in the control group to 32.2 percent in the treatment
arm. Chronic GVHD is a poorly understood and often
debilitating condition with a wide range of clinical
manifestations, and this reduction is therefore of great
significance for improving the quality of life for patients.
At this stage in reading the article, transplant physicians
would probably turn to the information on disease relapse
and might anticipate that this benefit of reduced GVHD
would be offset by an increase in disease relapse. But
the remarkable finding of this study is that there was no
statistically significant decrease in two-year relapse-free
survival associated with the use of ATG. Indeed, at this
point of follow-up, the percentage of patients who had not
relapsed and who remained free of chronic GVHD more
than doubled from 16.8 percent to 36.6 percent.
ATG is a three-day treatment course given prior to
transplantation, and the results of this study suggest that
it has an important role in this setting. It should be noted
that reduced-intensity conditioned transplantation is now
a common transplant regimen, and the role of ATG in this
setting remains uncertain. This is an important incremental
advance for clinical transplantation. However, the
observation that only 37 percent of patients remained free
of both disease relapse and chronic GVHD at two years
after transplantation indicates that further opportunities
remain to increase the efficacy and tolerability of this
extraordinary procedure.
To address these challenges, Dr. Elliot Stieglitz and colleagues performed a comprehensive genomic characterization of
primarily nonsyndromic JMML, with the goal of identifying new mutations to refine outcome prediction and to aid in the
development of new therapies. The authors first performed whole exome sequencing in 29 cases of JMML, comparing
paired germline and diagnostic tumor tissue. Tumor samples from progression or relapse were analyzed in a subset of
patients as well. The authors applied an innovative informatics algorithm to accurately distinguish somatic and germline
mutations, which was of critical importance because approximately 25 percent of patients are known to have inherited
syndromes that predispose to JMML.
Key findings from this analysis were the discovery of 10 new mutations in known oncogenes and tumor suppressor
genes to add to the list of mutations in five canonical Ras pathway genes (NF1, KRAS, NRAS, PTPN11 and CBL),
which have been previously implicated in the pathogenesis of JMML. These newly discovered genes are involved
in diverse processes, including signal transduction, splicing, transcription, and epigenetic regulation, and they help
introduce the possibility of treating JMML with existing targeted agents, such as Janus kinase (JAK) inhibitors or
epigenetic agents. All of the identified pathogenic mutations were validated in an independent cohort of 71 patient
samples using targeted deep sequencing.
Figure
a
1.00
Overall Survival (Proportion)
The administration of antithymocyte globulin (ATG) to
patients around the time of transplantation is one of
several approaches that have been introduced for T-cell
depletion. Compared with the sophistication of modern
targeted drugs, ATG has an almost elixir-like quality, as it
is made from the purified immunoglobulin of rabbits that
have been immunized with a human thymocyte cell line. In
their article, Dr. Nicolaus Kröger and colleagues performed
an open-label study in which ATG was administered in
the three days before transplantation in a cohort of 168
patients with a primary diagnosis of acute leukemia who
were undergoing myeloablative transplantation from a
sibling donor. Clinical trials have been challenging to
perform in the transplant setting, and the delivery of this
study is therefore a significant achievement in its own
right.
J
uvenile myelomonocytic leukemia (JMML) is a rare and unique form of childhood leukemia with both
myelodysplastic and myeloproliferative features and clinical and biological similarities to chronic myelomonocytic
leukemia (CMML) and chronic myelogenous leukemia (CML).1 The hallmark of this disease is hyperactive Ras
signaling. While JMML often arises within the context of an inherited syndrome, de novo cases occur as well.
Hematopoietic stem cell transplantation is presently the sole curative treatment option, but this has a success rate
of only approximately 50 percent overall. There is great variability in the clinical course of JMML, and one of the most
significant challenges in managing this disease is distinguishing children who will have favorable versus unfavorable
outcomes.
Log-Rank p = 0.834
0.75
0.50
0.25
0.00
NF1
KRAS
CBL
PTPN11
NRAS
Other
0248810
Time From Diagnosis (Years)
b
1.00
Overall Survival (Proportion)
S
ince the development of allogeneic stem cell
transplantation in the 1970s, the question of
how to optimize the number and activity of
donor T cells in the early transplant period
has dominated the development of transplant regimens.
Given the exquisite sensitivity of the immune system and
the substantial genetic differences between siblings, it
is no surprise that the donor immune system recognizes
the patient as “foreign” and mounts a vigorous immune
response. However, this alloreactive response is both
damaging, in that it mediates graft-versus-host disease
(GVHD), and beneficial, as it underlies the graft-versusleukemia effect that helps to reduce disease relapse. As
with many aspects of life, this balance has proven difficult
to achieve, and interventions such as vigorous T-cell
depletion, or the early infusion of additional T cells, have
both led to clinical problems.
0 or 1 alteration (n = 64)
2 or more alterations (n = 34)
0.75
0.50
0.25
P = 0.002
0.00
02 48 810
Time From Diagnosis (Years)
Numbers at risk
0 or 1 alteration
6445 3526 2116
2 or more alterations34
15
13
8
6
3
Patient outcomes stratified by canonical mutation and number of
somatic alterations. (a) Overall survival based on canonical mutation.
Individual canonical driver mutations were not associated with outcome (logrank p = 0.834). (b) Overall survival rates according to the number of somatic
alterations at diagnosis. Adapted by permission from Macmillan Publishers Ltd:
Nat Genet Volume 47 Pages 1326-1333, copyright 2015.
Additional key findings in this report
included the discovery of mutations
in SH2B3 in a subset of JMML
patients. Mutations in this tumor
suppressor gene lead to JAK-STAT
pathway activation. While mutations
in SH2B3 have been observed in
adult myeloproliferative neoplasms
and lymphoid malignancies, this
was the first report in JMML. The
genomic complexity of JMML was
further highlighted by the observation
that coexisting mutations in Ras
pathway and other genes were
identified in 11 percent of patients,
so not all Ras pathway alterations
are mutually exclusive. Furthermore,
mutations in epigenetic modifier
genes were observed in 14 percent
of patients and led to global
hypermethylation in those studied.
Finally, the authors illustrated several
examples of the acquisition of
secondary genetic events at the time
of disease progression or relapse.
The authors next analyzed the
prognostic contribution of genetic
mutational profile. Notably, they
observed that the number of somatic
alterations at diagnosis rather than
the specific mutation, determined
prognosis (Figure). Overall survival
rates at 10 years were significantly
better (65.1% ± 6.0% vs. 29.0% ±
8.3%; P = .002) in the 65 percent
of patients with zero or one somatic
alterations at diagnosis, compared
with the 35 percent of patients
who had two or more mutations.
Moreover, in a multivariate analysis,
the number of somatic alterations at
diagnosis was the most significant
predictor of outcome, exceeding
the prognostic impact of traditional
clinical risk factors.
There is great heterogeneity in the
clinical course of JMML, with some children experiencing spontaneous disease regression while others exhibit an
aggressive and rapidly progressive course. Some of the greatest challenges in the management of children with JMML
include this unpredictability in the clinical course as well as the limited number of effective treatment options. This
study by Dr. Stieglitz and colleagues sheds important new light on the pathogenesis and genetic complexity of JMML
and offers opportunities for both refinements in outcome prediction as well as the potential for development of novel
combinational therapies, targeting both driver and acquired secondary mutations.
1. Chang TY, Dvorak CC, Loh ML. Bedside to bench in juvenile myelomonocytic leukemia: insights into leukemogenesis from a rare pediatric leukemia.
Blood. 2014;124:2487-2497.
12
PAUL MOSS, PhD
ELIZABETH RAETZ, MD
Dr. Moss indicated no relevant conflicts of interest.
Dr. Raetz indicated no relevant conflicts of interest.
The Hematologist:
ASH NEWS AND REPORTS
P E R S P E C T I V E
DBDR Embraces Cross-Cutting Science: A Paradigm for the Future of Scientific Discovery
Interview with W. Keith Hoots, MD, Director, Division of Blood Diseases and Resources at the National Heart, Lung, and Blood Institute, part of the National Institutes of Health, Bethesda, MD
D
iscussions of cross-cutting science (CCS) have been percolating for quite some time. However,
in the field of hematology, there have been few opportunities to fully implement a collaborative,
interdisciplinary approach to solving problems, using diverse, unique perspectives. The Division
of Blood Diseases and Resources (DBDR) of the National Heart, Lung, and Blood Institute (NHLBI)
capitalized on an opportunity to give a lofty concept some real-world meaning, in the form of a divisionwide reorganization.
A third and very important CCS strategy for us entails
cross-institute (NIH) or cross-agency (e.g., the U.S.
Department of Defense [DoD]) collaborations. Not only do
such efforts often enable us to leverage shared funding for
common research endeavors, but they often allow entities
that are chartered to target research in diverse organ foci
to collaborate to undertake essential research at interfaces
between the organ-centric areas.
Dr. W. Keith Hoots, director of DBDR, spoke with The Hematologist and described how cross-cutting
perspectives are making a positive impact throughout the National Institutes of Health (NIH) and NHLBI, and
how they could lead to a new paradigm within the field for accelerating the pace of scientific discovery.
One example we are pursuing is a collaboration with the
National Institute of Neurological Disorders and Stroke
(NINDS) to engender new research into the blood-brain
barrier based on recent research showing the complex
interplay between the cells and circulating proteins of the
systemic circulation and their messaging to critical cells in
the central nervous system. In addition, we work closely
with our colleagues in the DoD to support research in the
coagulopathy of trauma and its treatment.
Can you describe the nature of the reorganization of
DBDR and what is prompting the change?
DBDR reorganized its structure to better align itself with
the research process — from laboratory investigations to
clinical trials to real-world implementation studies, and
back-to-basic investigations, with the various translational
steps in between these areas. With this reorganization,
DBDR is moving away from organizing itself by disease
category.
The new structure was established to permit DBDR to
adapt to a new reality in blood science — the growing
number of shared research pathways among scientists
from diverse disciplines. This new landscape is providing
opportunities for investigators to work in teams, and
particularly for hematologists to extend their reach into
disease areas not traditionally examined with the aid of
their knowledge and skills.
DBDR’s decision to reorganize is in line with current
activities of NIH and NHLBI in that both have initiated
new programs to optimize their research enterprises in
ways that cut across areas of expertise. At NHLBI, this is
referred to as strategic visioning. The goal is to catalyze the
development and implementation of bold, new approaches
that would be difficult for any individual researcher or
organization to undertake alone.
DBDR’s previous, more disease-focused branches were
the Hemostasis and Thrombosis Branch, Blood Diseases
Branch, and Transfusion Medicine and Cell Therapies
Branch. The new branches are Molecular, Cellular, and
Systems Blood Science (MCSB); Translational Blood
Science and Resources (TBSR); and Blood Epidemiology
and Clinical Therapeutics (BECT). Together, the new
branches create a scientific research loop from basic
discovery to translation to clinical trials to population
implementation and back to discovery (see Table).
How do you define cross-cutting science, and how
is this concept being incorporated into DBDR’s
mandate?
Cross-cutting science (CCS) serves as a primary rationale
for undertaking this reorganization. It is inextricably linked
to the need for team science since no single scientist or
lab can master all the nuances of multiorgan pathogenesis.
Teams of diverse individuals or groups approaching a
scientific question from alternative perspectives enable
a more integrated investigation that may increase both
the rate and the depth of discovery. Fostering these
collaborations is essential to our responsibilities as a
national research program charged with enabling blood
science.
In the context of our reorganization, we define CCS in at
least three ways: First, we define it in terms of science
that falls in the “gray zone” between the three branches,
requiring ongoing conversations between two or all three
branches. To expedite this essential dialogue, we are
creating project groups to develop new scientific initiatives
that do not fall neatly or exclusively into our organizational
niches. An example would be developing a pathway for
a newly developed drug to progress from first-in-human
safety studies to phase II efficacy studies, toward a pivotal
licensure trial. At a minimum, members from TBSR and
BECT would need to collaborate to chart the funding
course forward.
The Hematologist:
ASH NEWS AND REPORTS
A second definition of CCS includes the essential
collaborations across NHLBI. These CCS efforts can be
institutewide or bilateral efforts between DBDR and
either the Division of Lung Diseases or the Division of
Cardiovascular Sciences. With regard to the former, one
recent success has been the development of a sickle cell
disease (SCD) transinstitute collaborative: It will test
strategies to improve the incorporation of proven therapies
within the adolescent and adult SCD community. Other
examples of bilateral work between divisions include the
co-sponsoring of scientific initiatives in the pathophysiology
of sepsis/pneumonia with our colleagues in NHLBI’s
Lung Division and shared efforts with the Cardiovascular
Sciences Division to promote research in vascular biology
across the arterial-microvasculature-venous continuum.
Additional CCS enterprises that we are aggressively
supporting focus on the molecular and cellular
infrastructure that defines regenerative capacity in human
injury states. Efforts to define this process entail CCS
such as “organ on a chip,” induced pluripotent stem cell
development, and propagation and cell-cell cross-talk.
Organ-specific efforts are ongoing in multiple Institutes at
NIH. Yet the interinstitute collaborations being promoted
by the National Center of Applied Sciences (NCATS) are
playing an essential role in assuring that CCS scientific
initiatives will benefit from an integrated effort at NIH.
(Cont. on next page)
Table. New DBDR Branch Structure
Molecular, Cellular, and Systems Blood Science (MCSB)
The mission of MCSB is to advance basic research in blood science by stimulating, supporting, and overseeing: 1)
basic research in normal hematology and blood disorders; 2) technology development related to blood research in
academia and by small businesses; and 3) workforce training in basic and early translational blood science. More
specifically, MCSB is prioritizing the following:
• Understanding dysfunction of fundamental molecular and cellular mechanisms
• Harnessing the potential of “-omics” and nanotechnology to develop new diagnostics and therapeutics
• Facilitating the mechanistic understanding of immune tolerance to therapeutic proteins or gene transfer vectors
• Promoting stem and progenitor cell research and enabling early translation to cell therapy applications
• Supporting innovative next-generation technology for systems and precision medicine
• Providing opportunities to sustain and increase the discovery workforce in nonmalignant hematology
Translational Blood Science and Resources (TBSR)
The mission of TBSR is to advance translational research in all areas of blood science. This will be accomplished by
supporting and stimulating development of blood-focused therapeutics and the manufacture thereof. This will require
a focus on extending discovery science from bench to first-in-human studies. Furthermore, this branch will play a
particularly important role in coordinating training programs and in supporting small business research and development.
Future priorities for TBSR include the following:
• D
eveloping and maintaining strategic blood research resources (e.g., assay development and preclinical product
characterization capability)
• Facilitating team science to develop the next generation of animal models
• Developing the next generation of scientists with expertise in research translation
• W
orking within NHLBI and across NIH to assist investigators with regulatory requirements and commercialization
potential
• Facilitating improved design and execution of early phase clinical trials
Blood Epidemiology and Clinical Therapeutics (BECT)
The advancement of clinical research throughout the spectrum of blood science is the mission of BECT. To achieve
this aim, staff will oversee, support, and stimulate epidemiologic, health services, and observational research. They will
promote the design and execution of therapeutic and intervention trials. The efficacious outcomes from the latter will
generate comparative effectiveness and implementation research trials to measure effectiveness on population health.
It is expected that these aims will result in enhancement of innovative approaches for prevention and therapeutic trials
for rare diseases, and completion of societally important implementation trials of proven therapies. In addition, expected
outcomes include integrated clinical trials across the lifespan, optimized transfusion and cell therapy products across
broad populations, innovative methods to integrate and analyze data from population and cohort research, and “reverse
translation” from the community and bedside, back to the bench.
13
(Cont. from previous page)
What do you see as the potential impact of CCS on
the next wave of discovery and progress within the
hematologic community?
CCS will likely expand and expedite scientific discovery.
Through CCS and the team science that goes with it,
scientific discoveries in one area can more quickly catalyze
discovery in another area. Without CCS and team-based
science, such beneficial connections between areas of
expertise might take years to happen, if they happen at all.
By hematologists working with infectious disease experts,
for example, more may be learned and faster about bloodborne parasitic infections such as malaria, and particularly,
emerging blood-borne pathogens.
In addition to the intergovernmental collaborations noted
above, progress within the hematologic community will
depend on creative public-private partnerships dedicated
to CCS. For example, with the National Cancer Center,
we are creating a myelodysplastic syndrome (MDS)
resource that will permit longitudinal assessment of
genomic and epigenomic/transcriptomic changes within
hematopoetic progenitor cells in a cohort of patients
with MDS as compared with a contemporaneous cohort
of age-matched individuals with unexplained anemia/
thrombocytopenia (e.g., idiopathic cytopenias of
underdetermined significance [ICUS]). We hope that this
will provide molecular insight into what drives MDS and its
not-invariable progression to acute myeloid leukemia.
for applications (RFAs), requests for proposals, or program
announcements with review —referred to as initiatives.
Nonetheless, since DBDR proposals compete for initiative
monies based on scientific rationale and meeting a
scientific need or filling a scientific gap, it is our hope that
our new integrated approach will foster more enhanced
initiative proposals that will fare well within the institute.
Given the ASH Agenda for Hematology Research
and DBDR’s restructuring, how do you see our
professional organization and your agency working
together to synergize efforts?
The 2015 ASH Agenda for Hematology Research identified six
areas of priority for research support (including dedicated
resources from funding agencies): 1) genomic profiling and
chemical biology, 2) immunologic treatments of hematologic
malignancies, 3) genome editing and gene therapy, 4)
stem cell biology and regenerative medicine, 5) epigenetic
mechanisms, and 6) venous thromboembolic disease.
Aside from the second priority focused on hematologic
malignancies and immunotherapy (more appropriately the
province of the National Cancer Institute), DBDR shares
these priorities. As I have discussed above, for example,
regenerative medicine and stem cell biology are a focus of
both ongoing research support as well as our cross-cutting
emphases for future scientific emphasis. We are presently
supporting such efforts both through investigator-initiated
“The future of
CCS will be
dependent on
how well we
cultivate the
future research
workforce...
Attention to
every aspect
along the
educational
continuum,
including
enhancing
resources, will
be required.”
–W. Keith Hoots, MD, Division of
Blood Diseases and Resources
The future of CCS will be dependent on how well we
cultivate the future research workforce. Although federal
funding that has not kept pace with inflation has certainly
helped to create this challenge, there is a consensus that
money alone will not solve the problem. Attention to
every aspect along the educational continuum, including
enhancing resources, will be required: From early STEM
education in primary and secondary schools to shortening
of the research career trajectory to support of midcareer MDs, MD-PhDs, and PhDs. Enhancing all of these
educational areas and the development of many other
creative strategies are needed to meet this challenge. DBDR
is committed to collaborating with all partners to address
this most critical of challenges.
How does the reorganization affect funding
opportunities and priorities within the NHLBI?
The reorganization of DBDR is revenue neutral for DBDR
and NHLBI. It will not affect the funding of investigatorinitiated research applications (e.g., R01s, P01s, etc.). It
also will not affect the total funding available for requests
14
research project grants as well as targeted initiatives such
as the RFA for basic stem cell biologic approaches to blood
“pharming” (R01) and the technological applied research
to support this effort (e.g,, through the Small Business
Innovation Research [SBIR] and Small Business Technology
Transfer [STTR] programs).
With regard to genomic profiling, we are presently
participating in the NHLBI TOPMED (Trans-Omics for
Precision Medicine) program, which is underwriting
whole genome sequencing for existing NHLBI cohorts.
For DBDR, this translates to a commitment to sequence
DNA from patient cohorts with SCD, hemophilia, platelet
disorders, and venous thromboembolism (VTE). (SCD was
an ASH priority for 2014.) All of the hematologic cohorts to
undergo DNA sequencing will have extensive phenotyping
performed longitudinally over several years. This will
permit a careful scrutiny of yet-to-be characterized genes of
influence in the monogenic diseases such as SCD and will
allow an exonic and intronic examination of the “acquired”
polygenic diseases such as VTE. Furthermore, in relation to
the ASH priority of deciphering epigenetic mechanisms, the
long-term strategy for TOPMED is to supplement the whole
genome sequencing with targeted epigenetic sequencing.
Ultimately, these efforts should provide an important
foundation for precision medicine for patients with both
common and rare hematologic diseases.
Gene transfer has been a mainstay of DBDR translational
research efforts for nearly two decades. We have provided
vector production support for multiple phase I trials on
hemophilia B, for example. More recently, investigators we
support by both R01 grants and targeted RFAs are doing
seminal work in gene editing for SCD and severe combined
immune deficiencies. We have supported work utilizing
editing strategies for zinc-finger nucleases and the TALENS
and CRISPR-Cas9 enzymes for SCD and thalassemia. Under
the reorganization, the TBSR Branch is developing a
long-term strategy for scientific and resource support for
advanced gene transfer and gene editing to move toward a
cure for multiple monogenic hematologic diseases.
Finally, with regard to VTE, DBDR is exploring with our
colleagues at the National Cancer Institute (NCI) strategies
to understand more extensively how cancer predisposes
patients to pathogenic clotting — a collaborative approach
that will likely engage all three of our new branches.
We think that combining the oncologic expertise of
investigators funded by NCI and the cohorts they have
assembled with the basic, translational, and clinical
coagulation expertise of DBDR-funded thrombosis
investigators offers unique opportunities to extend our
knowledge in this important clinical area.
Which of DBDR’s accomplishments are you most
proud of during your tenure there and what is an
example of a concrete endpoint you’d like to see
DBDR achieve with the reorganization?
I am most proud of the team that we have assembled to
accomplish the DBDR reorganization. It consists of some
very experienced and dedicated scientists who have
shepherded hematologic research over several decades and
some newer arrivals who have brought new enthusiasm and
new expertise that will enable DBDR to pursue the long-term
goals discussed above. I am particularly indebted to the
DBDR Deputy Donna DiMichele and the Branch Chiefs of the
reorganized Branches (the DBDR Leadership Team) who
have helped to engineer the process and spread the word
across the “Heme” community about the how, why, and
when of the reorganization. Already, we are seeing both new
avenues of science (for DBDR) being pursued and broad
resources being leveraged to enhance capacity.
We are very proud of the new SCD initiative for
implementation science and the successful collaboration of
DBDR with DoD and the NHLBI Division of Cardiovascular
Sciences to complete the “PROPPR” (Pragmatic
Randomized Optimal Platelet and Plasma Ratios) trial of
transfusion components for severe trauma. We are also
proud of the DoD-DBDR Trans-Agency Collaboration in
Trauma-Induced Coagulopathy (TACTIC), the substantial
translational initiatives in both hemoglobinopathies and
hemostasis/thrombosis, and the other programs cited
above. Additionally, we are proud of the work we have
done to enhance opportunities for the next generation of
researchers in blood science and are determined to further
enhance efforts in this area.
A particularly important example of what would constitute
a concrete endpoint for us is to increase the number of
investigators nationally who research blood science.
Achieving this will require close work with many other
stakeholders including ASH. We must turn the curve on the
declining research workforce in blood science. Multiple
strategies across many organizations and agencies will be
required. The pursuit of great science is, we believe, worth
the effort.
Dr. Hoots indicated no relevant conflicts of interest.
The Hematologist:
ASH NEWS AND REPORTS
Clinical Trials Corner
Editors’ Choice
JAN UARY 21, 2016
Wei Y, Ji X, Wang Y, et al. High-dose dexamethasone
vs prednisone for treatment of adult immune
thrombocytopenia: a prospective multicenter randomized
trial. Blood. 2016;127:296-302.
In this issue, Dr. Yu Wei and colleagues report the
results of a uniquely large and long-awaited prospective
randomized trial of high-dose dexamethasone (HD)
versus standard-dose prednisone (PDN) for the
treatment of newly diagnosed adult primary immune
thrombocytopenia (ITP). HD gives a shorter time to
response and a higher rate of initial response, as well
as less toxicity, and represents a preferred treatment
strategy in the first-line management of ITP.
Dr. Bob Löwenberg (Editor-in-Chief) and Dr. Nancy Berliner
(Deputy Editor-in-Chief) have combined efforts to identify
some of the most outstanding Blood articles that have
appeared either in print or online during the two-month
interval between issues of The Hematologist. The goal is
to underscore the remarkable research that is published in
Blood and to highlight the exciting progress that is being
made in the field.
D E C E M B E R 1 7, 2 0 1 5
O’Brien SM, Lamanna N, Kipps TJ, et al. A phase 2 study
of idelalisib plus rituximab in treatment-naïve older
patients with chronic lymphocytic leukemia. Blood.
2015;126:2686-2694.
The therapy of chronic lymphocytic leukemia (CLL)
has been transformed over the last several years by the
introduction of novel immunotherapies. In this week’s
Blood, Dr. Susan O’Brien and colleagues present the
first trial of up-front therapy with the PI3Kδ inhibitor
idelalisib in older patients with CLL. They show a
remarkable 97 percent response rate, with excellent
progression-free survival, albeit with significant toxicity.
DECEMBER 24, 2015
Menger L, Gouble A, Marzolini MA, et al. TALENmediated genetic inactivation of the glucocorticoid
receptor in cytomegalovirus-specific T cells. Blood.
2015;126:2781-2789.
In their plenary paper in this week’s Blood, Dr. Laurie
Menger and colleagues report a novel gene editing
strategy that disrupts the glucocorticoid receptor and
renders cytomegalovirus (CMV)-specific T cells resistant
to steroids while retaining antiviral functions. This study
addresses an unmet clinical need: how to infuse CMVspecific T cells into transplantation patients receiving
steroids.
Hua VM, Abeynaike L, Glaros E, et al. Necrotic platelets
provide a procoagulant surface during thrombosis. Blood.
2015;126:2852-2862.
Necrotic platelets are a procoagulant subpopulation
of activated platelets that are formed in response to
a strong in vitro stimulus. In this issue, Dr. Vu Minh
Hua and team use a novel marker of platelet activity to
demonstrate that necrotic platelets uniquely contribute
to fibrin formation and platelet accumulation within the
forming thrombus.
J A N U A R Y 7, 2 0 1 6
Bride KL, Vincent T, Smith-Whitley K, et al. Sirolimus is
effective in relapsed/refractory autoimmune cytopenias:
results of a prospective multi-institutional trial. Blood.
2016;127:17-18.
In their plenary paper, Dr. Karen Bride and coauthors
report the safety and efficacy results of a unique
prospective multi-institutional trial using sirolimus as
long-term monotherapy in 30 patients with a variety of
treatment-refractory autoimmune hematocytopenias,
with highly encouraging results. They show particularly
remarkable long-term efficacy in the 12 children with
autoimmune lymphoproliferative syndrome.
Thompson PA, Tam CS, O’Brien SM, et al. Fludarabine,
cyclophosphamide, and rituximab treatment achieves
long-term disease-free survival in IGHV-mutated chronic
lymphocytic leukemia. Blood. 2016;127:303-309.
In this week’s Blood, Dr. Philip Thompson and
colleagues report their remarkable long-term results
of the use of fludarabine, cyclophosphamide,
and rituximab (FCR) — the gold standard of
chemoimmunotherapy for younger patients with
previously untreated chronic lymphocytic leukemia
(CLL). The study demonstrates a plateau on the
survival curves for patients with mutated IGHV, raising
the possibility of cure in a subset of patients. These
data furnish strong support for clinicians to use FCR
as the standard of care. They also reinforce FCR as
the reference regimen for comparing the therapeutic
efficacy of combinations of novel agents in younger
patients.
JAN UARY 28, 2016
Dahlin JS, Malinovschi A, Öhrvik H, et al. Lin- CD34hi
CD117int/hi FcεRI+ cells in human blood constitute
a rare population of mast cell progenitors. Blood.
2016;127:383-391.
Mast cells are involved in allergic reactions, and
increased numbers of mast cells are characteristically
found in the lungs of patients with asthma. The cell of
origin of the mast cell has been elusive. In this week’s
plenary paper, Dr. Joakim Dahlin and colleagues have
identified a rare human progenitor cell (CD34hi CD117int/
hi
FcεRI+) that is committed to mast cell maturation;
these immediate mast cell precursors are increased
in the lungs of patients with asthma and reduced lung
function.
FE B R UARY 4, 2016
Zhou L, Hinerman JM, Blaszczyk M, et al. Structural basis
for collagen recognition by the immune receptor OSCAR.
Blood. 2016;127:529-537.
In a pioneering contribution, Dr. Long Zhou and
coauthors present a wealth of information about the
biologically important collagen-activated osteoclastassociated receptor (OSCAR) and its interaction
with collagen. They report the crystal structure of
a collagen model peptide with a leukocyte receptor
complex-encoded collagen receptor. Their findings
provide new insights into the molecular mechanism of
OSCAR-collagen interactions and create a foundation for
potential therapies for a variety of diseases.
Karol SE, Mattano Jr LA, Yang W, et al. Genetic risk
factors for the development of osteonecrosis in children
under age 10 treated for acute lymphoblastic leukemia.
Blood. 2016;127:558-564.
In this issue of Blood, Dr. Seth Karol and colleagues
report the first study that addresses the molecular
predisposition to osteonecrosis, one of the most
debilitating therapy-related medical complications in
childhood acute lymphoblastic leukemia.
Chemotherapy as a Double-Edged
Sword: Figuring out Who Pays the
Price Later
STUDY TITLE: N-PhenoGENICS: Neurocognitive-
Phenome, Genome, Epigenome and Nutriome in
Childhood Leukemia Survivors CLINICALTRIALS.GOV IDENTIFIER: NCT01913093
SPONSOR: The Hospital for Sick Children, Toronto,
Ontario, Canada
COLLABORATING CENTERS: Canadian Institutes of
Health Research (CIHR), Canadian Cancer Society
Research Institute (CCSRI), C17 Council, Garron
Family Cancer Center at the Hospital for Sick Children,
Pediatric Oncology Group of Ontario
ACCRUAL GOAL: 500 patients, estimated at 100 patients
per year for five years from 2013 to 2018
STUDY DESIGN: The N-PhenoGENICS trial is a
prospective observational case control study with a
primary outcome measure to define neurocognitive and
behavioral phenotypes of childhood leukemia survivors.
The two cohorts will be leukemia survivors aged
between eight to 20 years with or without treatmentrelated adverse neurocognitive effects (TRANCE) trait.
The trial will focus on children with a past diagnosis of
acute lymphoblastic leukemia (ALL) who had received
their last treatment two years prior to enrolling
on this study and who are in continuous complete
remission. Patients who had undergone bone marrow
transplantation or who had a Down Syndrome diagnosis
are not eligible.
RATIONALE: Chemotherapy for childhood ALL has
been effective, but in some cases, it may lead to
long-term adverse side effects including abnormal
neurocognitive function and behaviorial problems,
collectively classified as the “TRANCE” phenotype, in
some survivors. The hypothesis underlying this study is
that individual genetic variations in folate pathways and
the metabolism of methotrexate are associated with the
TRANCE phenotype. To explore these aspects, the study
investigators will characterize the folate and vitamin
B12 intakes of these children to establish whether there
are significant differences that may influence folatedependent pathways. To identify possible epigenetic
mechanisms underlying this phenotype, DNA samples
will be obtained from both study cohorts and analyzed
for methylation patterns.
COMMENT: In the past few decades, the overall survival
rate for children’s cancers has increased from 10
percent to nearly 90 percent, but long-term follow-up
studies have revealed that this success has come with
a price. Approximately 60 percent of children who
remain in complete remission suffer devastating late
effects such as secondary cancers, muscular difficulties,
infertility, and neurocognitive abnormalities. This raises
the question as to why only some children develop
these adverse effects. Are there polymorphisms in
critical genes that confer a protective effect? Could
epigenetic phenomena play a role? What is the
contribution of important nutrients such as folic acid
and vitamin B12? To answer these questions, a new
phase of research is required. The investigators in this
study have chosen children who have survived ALL as
a model to try and explain the selective development
of detrimental side effects. They are embarking on the
initial steps to identify differences between children
with adverse events and those who have not developed
any symptoms to uncover the underlying molecular
characteristics driving this susceptibility. Their ultimate
goal will be to find target molecules or pathways that
may be amenable to therapeutic intervention. This will
be the first step toward improving the long-term quality
of life for children who have survived cancer.
–Theresa Coetzer, PhD
Dr. Coetzer indicated no relevant conflicts of interest.
The Hematologist:
ASH NEWS AND REPORTS
15
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MARK YOUR CALENDAR
W E B
As technology and the Web have evolved, so too have ASH’s
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download ASH apps for your smartphone or tablet, follow ASH
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March
5-6
Highlights of ASH in Asia-Pacific
Brisbane, Australia
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72016 Minority Medical Student Award Program applications due
Washington, DC
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15
ASH-AMFDP Award applications due
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25
Latin American Training Program applications due
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25
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31Visitor Training Program applications due
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April
6
Nomination packages due for the 2016 ASH Mentor Award
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27-28 CRTI in Latin America
ASH On Demand: 2015 ASH Annual Meeting Complete Meeting
As the premier event in malignant and non-malignant hematology,
the ASH annual meeting provides attendees with an outstanding
educational experience that examines the latest clinical advances
in hematology and explores the year's most significant scientific
discoveries and updates. The videos make this event available for
convenient, on-demand viewing.
ASH now offers three package options, where you can choose between
scientific and educational content, or purchase both at a lower price.
The 2015 ASH Annual Meeting webcast (full package) includes all of the
following sessions:
• General Sessions
Natal, Brazil
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29-30Highlights of ASH in Latin America
Porto Alegre, Brazil
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May
2 Scholar Awards letter of intent due
Washington, DC
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June
18-21ASH Meeting on Lymphoma Biology
Colorado Springs, CO www.hematology.org/lymphoma-biology
• Special-Interest Sessions
• Trainee Simultaneous Didactic Sessions
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New Membership Category for International Trainees
Continuing the Society's evolution as a global organization and to engage
early career scientists from around the world, ASH has established a new
membership category, International Associate. This enables trainees outside
North America to join ASH and access member benefits similar to Associate
members in North America – including complimentary subscriptions to ASH
publications, discounts on various educational resources, and exclusive
annual meeting discounts and opportunities. Physicians in a hematology or
hematology-related training program and students in a post-doctoral position
in a hematology-related field residing outside North America are eligible to
become International Associate members and are encouraged to find out
more information and apply by visiting www.hematology.org/membership.