Sometimes a cell line isn't what the researchers think it is.
As Retraction Watch reports, cell line contamination has led to the retraction of a 2012 PLOS One article that examined pathways involved in resistance to anoikis in adenoid cystic carcinoma. But, after a reader raised concerns with the journal, the study authors from Wuhan University submitted their lines for analysis, and that analysis revealed cross-contamination from HeLa cells in the ACC2 and ACCM lines they used.
"The authors have completed a short tandem repeat analysis on the cell lines and this has revealed cross-contamination with other human cells, which compromises the relevance of the work to human adenoid cystic carcinoma, and thus the conclusions of the study," the retraction notice says.
Retraction Watch notes that previous reports have found that somewhere between a fifth and a third of cancer cell lines tested have been contaminated.