Opinion
2-2012
Lab Times
page 41
What’s behind paper retractions? (8)
Can We Trust Western Blots?
Not without more transparency and scrutiny.
Photo: zettberlin / Source: PHOTOCASE
H
ave you heard the one about the manipulated Western blots?
You probably have – but it’s no joke.
The technique – which Lab Times readers will know is a way
to separate proteins by structure or size – has been around for
about three decades and is widely used in science. Pictures of the
gels that result might be highly valuable for researchers trying
to demonstrate an effect but they also seem to be the method of
choice for image manipulators trying to make their results look
better than they really are.
Such manipulation, which often
involves using the same controls multiple times, has brought down more
than 30 papers by cancer researcher Naoki Mori, left the career of resveratrol scientist Dipak Das in serious question, and forced the resignation of cardiology researcher Zhiguo
Wang. And those are just a few of the
most visible cases. As we noted in a
previous column for this magazine
(LT 1/2012, p. 43), the US Office of
Research Integrity estimates that image manipulation – not only of Western blots – has grown from less than
ten percent of the cases it sees to almost 70 percent in just twenty years.
After one case of bogus Western blots, involving what a researcher said was a mistake, a Retraction
Watch reader suggested that maybe the blots themselves are the
punch lines: “Western blots have become a joke in published papers due to the failure of researchers to perform proper controls/
replicates and the failure of reviewers to demand this data.”
But flawed though Western blots may be, could researchers
get by without them? We doubt it; eliminating them from science
would be neither realistic nor wise. Our commenters, including
the one who thought they had become a laughing stock of the
lab, had some suggestions:
“At a minimum, relevant bands should be quantitated (e.g. LICOR or phosphoimaging) with n=3, normalised to a reference
protein and reporting mean and SD. No conclusions without p
values. Entire gels need to be shown and should include controls
for antibody specificity. All specifics about the detection method should be reported (time exposed to secondary antibody, an-
tibody concentrations, time exposed to developer, type of film,
etc.).”
“Uncropped, full images of Westerns should be required to
be submitted as supplemental material. I have seen people using
cropped Western blots and then found out later that they were
showing a non-specific band and not the actual protein of interest!”
We think these are reasonable ideas – coming, as we’ve
learned, from two people who’ve worked in labs – and, in fact, so
do some journals. Nature asks its authors to include “positive and
negative controls, as well as molecular size markers” on each gel
and blot, “either in the main figure or an expanded data supplementary figure”.
Nature recognises that cropping gels can improve “the clarity
and conciseness of the presentation” but requires that such “cropping must be mentioned in the figure legend and the supplementary information should include full-length gels and blots wherever possible”. Nature includes a number of specific recommendations and requirements, as does Nature Cell Biology.
For example, from the latter’s author instructions: “Avoid
splicing different gels together. If unavoidable, clearly demark the
point of splicing and avoid overextending quantitative interpretations across splices.” And: “As a minimum, provide uncropped
data at the submission stage to facilitate peer review.”
That’s an important reminder that peer review should be another gatekeeper for doctored images. Based on the ease, with
which Retraction Watch readers seem to spot manipulation once
we post items on unclear retractions, we’re confident reviewers
can do the same, if they’re actually looking. (Although, in fairness to reviewers, we’ll stipulate that hindsight here sometimes
appears a bit better than 20/20). And if journals are checking for
such doctoring, the way the Journal of Cell Biology began to in
2002, that’s another checkpoint.
Finally, we’d suggest being as specific as the Nature journals,
rather than leaving it to authors to define what should be disclosed, as the New England Journal of Medicine does: “Please describe and clearly indicate all modifications, selective digital adjustments, or electronic enhancements in all digital images.”
Why trust the kinds of authors who are likely to doctor images
in the first place to tell you what they’ve done?
Adam Marcus and Ivan Oransky
(The authors run the blog Retraction Watch:
http://retractionwatch.com)