The difference between a cow and a monkey is obvious. It is easy to tell a moth from a mosquito. So why are there still scientific studies that combine them? The answer is simple: hundreds of cell lines stored and used by modern laboratories have been incorrectly identified. Some pig cells are labeled as coming from chicken; The content of hamsters, rats, mice and monkeys is shown in the cell lines advertised as human.
Which is worse: that such crude mixtures exist, or that, every day, researchers use cell lines that someone, somewhere, has already found to be mislabeled, misidentified, or contaminated? Solving the first problem is a major challenge. Addressing the second is a more manageable task, and one that should be taken seriously by researchers, journals, universities and funders.
The journals Nature and Nature Research are strengthening their policies to improve the situation. Starting next month, we will ask the authors to check that they are not working on cells that have been misidentified or cross-contaminated, and ask them to provide more details about the source and testing of their cell lines. Will say for
This may seem like an obvious way to tackle a problem that has been known for decades. But tests to examine the contents of cell lines are complex and time-consuming, and until recently were expensive. Increasing awareness of the problem among scientists in some communities (especially cancer research), the availability of appropriate tests and resources (see JR Masters Nature 492, 186 (2012) and p 307), and how to deal with the matter The will of some funders — including the US National Institutes of Health and the Prostate Cancer Foundation in Santa Monica, Calif.
Problems have already been found with over 400 cell lines. In the long term, the goal should be to change testing routines around the world to ensure that new blends are not promoted. The least that scientists should already be doing is checking whether the cell line they are using is already marked with a red flag.
In 2013, the journal Nature began asking authors to report the source of their cell line and whether the cell line had been certified. Most have not done so. Of the sample of nearly 60 cell-line-based papers published in several Nature journals over the past two years, about one-quarter did not report the source.
Only 10% of authors stated that they had authenticated the cell line. This is particularly problematic because about one-third said they had received the cell lines as gifts from another laboratory.
Starting May 1, all authors of papers involving cell lines to be submitted to the journal Nature will be asked whether they have checked their cell lines against publicly available lists of those known to be problematic. We will specifically monitor compliance in cancer research.
Focusing on cancer is the first step, chosen because the cell-line problem has been best documented in this area, and because the cancer community is already responding to the issue. Some specialist journals, such as the International Journal of Cancer, are now calling for systematic certification. This is important not only for its effects on basic research, but also because of the potential for translational research to founder when cell lines are contaminated.
Other areas are not untouched by cell-line problems, and we look forward to expanding systematic investigations for them in the future. More information about the new policy, who it affects and where cell lines should be tested, are available at go.nature.com/zqjubh.
If a cell line used in a research project appears on the watch-list, it is not required to invalidate the research, or mean that the paper will be automatically rejected. The authors will be asked to explain why misidentification does not undermine the findings. But we reserve the right to ask for the data to be removed if the justification is deemed inadequate by the editors and referees.