Hundreds of scientists who study cancer and aging have made an easily avoidable but significant mistake, deploying the wrong antibody to test for a key protein, according to a researcher who exposes errors in the biomedical literature. Instead of antibodies that recognize p16INK4a, a tumor-suppressing protein that may also promote aging, these researchers used antibodies that tag the similarly named protein p16-ARC, which helps shape the cell’s molecular skeleton.
The gaffe appears in more than 300 papers, including some published by top journals such as Nature, Nature Medicine, Cancer Cell, eLife, and Science Advances, reports Sholto David, a molecular biologist at the U.K. biotech OXB and a part-time error hunter. David’s latest revelations, posted on 2 June on the blog For Better Science, have sent researchers digging through old lab notebooks and, in at least one case, back to the lab to rerun experiments.
The blunder is embarrassing and calls some results into question, scientists whose papers were not on the list of offenders say. “It won’t change what we know about p16’s role,” says molecular geneticist Christin Burd of Ohio State University. But “there needs to be some correction of the record.”
Antibodies are useful lab tools because the immune proteins bind to specific targets. The versions that clamp on to p16INK4a, which researchers might employ to, say, pinpoint cells that are producing the protein, “have been useful in thousands of studies of cancer and aging,” says Charles Sherr, a cancer biologist at St. Jude Children’s Research Hospital. The protein is part of a pathway that halts the cell cycle, the series of events that prepares a cell to divide, and thus curtails growth of tumors. P16INK4a also spurs cells to enter a nondividing state known as senescence that may cause some of the tissue deterioration of aging.
David is well-known for uncovering scientific errors, including misconduct. He recently identified problems in data posted by antibody seller Thermo Fisher Scientific. Last year he won $2.63 million from the Dana-Farber Cancer Institute after filing a False Claims Act case that documented dubious images and data in papers from the organization’s researchers.
He stumbled on the new screwup while delving into cancer cell lines that allegedly produce p16INK4a even though they were known to lack the gene for the protein. When he entered the term “p16” on the website of the antibodymaker Abcam, the first entry that popped up was for an antibody that targets p16-ARC. Other companies also offer both antibodies. David wondered whether other researchers shared his initial confusion and ended up ordering the wrong products.
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David then checked the antibody product codes listed in 334 studies of p16INK4a or p16-ARC to determine whether the researchers had used the right antibody. In 312 of the studies, researchers enlisted p16-ARC antibodies to probe for p16INK4a. The oldest papers date back more than a decade, which “tells you something about the process of biological research that it could go on so long without anyone noticing,” David says.
In some cases, David acknowledges in his post, a team may actually have used the correct antibody but listed the wrong one in the paper. That turns out to be the case for one of the most prominent studies he flagged, a 2019 Nature paper from molecular biologist Jan Karlseder of the Salk Institute for Biological Studies and colleagues that probed a mechanism for culling precancerous cells that doesn’t involve senescence. The researchers needed the antibody to test whether cells made p16INK4a. Karlseder says that after diving into lab records, his team confirmed it ordered the correct antibody—and he has a receipt from the seller to prove it. But the team entered the wrong product number in the methods section of the submitted paper. Karlseder and colleagues have sent a correction to Nature, he says.
Stem cell biologist Simon Leedham of the University of Oxford, whose 2015 Nature Medicine paper on the origins of colon cancer also made David’s list, admits his group used both antibodies; the team is now replicating the relevant experiments with just the p16INK4a antibody to make sure the results are correct. But Leedham says he and his colleagues had other supporting evidence for their conclusions.
Also worrisome, David says, is that researchers who used the wrong antibody sometimes reported results that would only make sense if they had used the right one. Sherr also finds that behavior disturbing. “This is an indictment … of the ability of people to conjure stories based on flawed data.”
David says some of the research teams likely committed fraud—at least four of the papers had been retracted even before he called out the antibody glitch. Other teams, he wrote in his post, may have been guilty of “selective reporting, writing errors, and … blindly publishing contradictory findings without further questioning or curiosity.”
“I can understand how this nomenclature can cause a lot of confusion,” says gerontologist Tien Peng of the University of California San Francisco. But a little more care could have helped researchers avoid the blunder. For instance, if they had run negative controls, testing cells that lack p16INK4a, they would have seen something was wrong, Burd says. Moreover, scientists should know they can’t rely on p16INK4a antibodies alone to detect senescent cells, Peng says. “There is no one marker for senescence.”
Although confusing terminology may have been the root of the problem, Sherr says it’s too late to change the names of the proteins—they are already established in the literature. And busy reviewers can’t police every product code in a paper, Burd says. But journals could help, she says, by flagging submissions that mention problematic antibodies so that reviewers can check whether the authors made the right choices.
Ultimately, Sherr says, David’s exposure of these blunders could benefit the field. “I don’t see how this is easily corrected except by embarrassing the people who have done it.”
