Latina farmworkers of the San Joaquin Valley with polymorphisms in xenobioticmetabolizing genes have elevated risk of breast cancer !
Yesenia Ibarra*, Malika Sahni*, Kathryn Patterson*, Jessica Borba*, Jason Bush*†, and Paul Mills†!
†
!
*Department of Biology, California State University, Fresno
Department of Internal Medicine, UCSF-Fresno!
Objective!
Results!
!
! !The goals of this study were to determine the association between exposure to organochlorine pesticides and breast
cancer risk in the Hispanic (Latina) female population of the intensely agricultural San Joaquin Valley of California by
assessing single nucleotide polymorphisms (SNPs) in select xenobiotic-metabolizing genes. !
.
!
Background!
v  In 2010, 207,090 cases of female breast cancer were diagnosed leading to more than 39,840
fatalities in the United States. In California alone there was 21,130 new cases (American Cancer
Society, 2010). !
v  California is the leading state of agricultural produce in the United States. There has been a wide
range of research correlating cancer with pesticide usage. !
v  A common class of pesticides, organochlorines (OC), resembles the structure of estrogen and are
collectively called xenoestrogens (environmental estrogens). Exposure and accumulation of
xenoestrogens are known to have profound effects on women s health including in utero
feminization, breast growth and lactation, and breast cancer. !
v  The pathway to xenobiotic elimination from the
body is a multi-step process resulting in excretion
of contaminants through the urine or bile. The first
step involves oxidation which is thought to be
primarily carried out by the Phase I enzyme family,
cytochrome P450 (CYP), and is typically an
activating reaction creating a more polar
byproduct. !
Figure 1. GSTM1 GSTT1!
Figure 2. GSTP1-I105V-RFLP !
v  The second step involves conjugation with an
endogenous ligand through a Phase II enzyme
family, glutathione-S-transferase (GST), and is
typically a detoxifying reaction!
Figure 3. GSTP1-A114V-RFLP !
Figure 4. CYP1A1-T6235C-RFLP !
HPAF-II!
Figure 5. CYP1A1-A4889G Sequence Analysis!
Methodology!
!
P4.03!
•  42 Female Hispanic participants!
BxPc-3!
.!
1. Oragene Kits!
•  DNA extractions from Oragene
kits1!
Figure 6. CYP1A1-C4887A Sequence Analysis!
Sensitive MDA-MB-231 Mitochondria!
•  PCR using annealing primers2!
Resistant (T13) MDA-MB-231 Mitochondria!
•  PCR product goes to 1 of 3 paths!
2. Thermal Cycler!
3. Sequence
Chromatograph!
Figure 7. CYP1A1-T6235C Sequence Analysis!
•  (A) Sequencing3!
!
•  (B) Restriction Fragment Length
Polymorphism with gel
electrophoresis4!
!
Acknowledgements!
4. Restriction Digest!
5. Gel Electrophoresis!
•  (C) Gel Electrophoresis5!
electrophoresis6
•  Analysis of gel
and sequence chromatogram
(Figure 5, 6, 7) !
Discussion and Future Directions!
6a. RFLP Results!
6b. PCR Gel Electrophoresis!
This research was funded by the
California Breast Cancer Research
Program grant No. 14IB-0032 and the
Susan G. Komen for the Cure grant.
The study was possible with the
collaboration of Dr. Paul Mills at UCSF
Fresno !
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GSTM1 null: No significance on breast cancer risk (O.R.=0.99, 95% CI=0.28, 3.51)!
GSTT1 null: Breast cancer risk doubled (O.R.=2.21, 95% CI=0.39, 12.63)!
CYP1A1:!
-Codon 119 Ala/Ser: No association with breast cancer risk (O.R.=0.77, 95%
CI=0.14, 3.70)!
-Codon 432 Val/Leu: Elevated risk of breast cancer (O.R.=2.33, 95% CI=0.64, 8.54)!
Although this study had a low number of participants, it indicates that it is
feasible to identify, trace, consent and recruit female Hispanic women in the San
Joaquin Valley of California who have recently been diagnosed with breast
cancer. !
!