No publication without authentication

Cells that are grown in the Petri dish are indispensable tools in biomedical research. From cancer research to neurosciences, from immunology to virology: In all conceivable disciplines, scientists use cell cultures to examine, for example, the effects of new drugs, responses to signaling molecules, or the infectious behavior of pathogens.

However, it is quite common that the cells that grow in the red culture medium are not what the researchers believe them to be. In the hustle of laboratory routine, it happens that tiny drops of culture medium are accidentally transferred from one container to another. If rapidly growing cells are introduced into other culture dishes in this way, they may swiftly outnumber other cells. Another critical issue is the permanent use of genetically variable cancer cells in laboratory experiments. These cells evolve over time by continuous mutations and after a while they no longer correspond to the initial cells. Frequently, however, the problem is simply caused by wrong labeling.

"A large share of the often criticized irreproducible results in biomedical research is attributable to misidentified or cross-contaminated cells," said Peter Lichter from the German Cancer Research Center (Deutsches Krebsforschungszentrum, DKFZ) in Heidelberg, who is the chief editor of the International Journal of Cancer. "There are estimates saying that up to 46 percent of all cell cultures are mislabeled. In the end, this substantially slows down medical progress."

However, scientists are not helpless victims of these mistakes. There are tests available to detect a cell line's identity with absolute certainty such as by analyzing genetic profiles (single nucleotide polymorphisms or short tandem repeats). Since 2013, the German Cancer Research Center has obliged its staff scientists who submit results for publication in specialist journals to first perform one of these tests on the cells that they have used.

Since 2010, the International Journal of Cancer (IJC), most of whose editors are DKFZ researchers, has made it a requirement for publication of articles that authors provide a genetic authentication for the cell lines used. Hence, the specialist journal is among a small number of journals that have taken a pioneering role in quality assurance of scientific results.

"We had first established contact with other scientific journals and funding organizations in order to resolve this problem as a community", Lichter said. "But when we could not reach a consensus, Harald zur Hausen, who was editor-in-chief at the time, decided that IJC would take this step alone."

The change brought considerable additional workload and costs for the IJC editors, they now report in the online research journal PLOS Biology*. It is particularly time-consuming to guide authors comprehensively on all necessary processes. "But it has been worth it," Lichter added. While a particular cell line that is known to have been misidentified is still being used in publications of other journals, it has not appeared in IJC since 2013. "The most important thing is that we are thus contributing to true advances in cancer research, which we hope will ultimately also be for the benefit of patients."

*Norbert E. Fusenig, Amanda Capes-Davis, Franca Bianchini, Sherryl Sundell, Peter Lichter:
The need for a worldwide consensus for cell line authentication: Experience implementing a mandatory requirement at the International Journal of Cancer.
PLOS Biology 2017, https://doi.org/10.1371/journal.pbio.2001438