Do you know your cell lines?

We all work with various cell lines. Sometimes those have been in the lab for a long time. Sometimes they are older than you. So how do you know you're still working with the right cell line, that the passaging hasn't completely changed the properties of the cell or that worse, they have been contaminated with another line. I vividly remember a talk from an older well respected researcher who candidly recalled how she wasted years studying a strange cell that happened to be a hybrid of her cancer cell line and a mouse fibroblast cell. Even the HeLa cells, the bread and butter of cell biology, are know to easily contaminate other cells lines:

"Because of their avid adaptation to growth in tissue culture plates, HeLa cells are sometimes difficult to control. For example, they have proven to be a persistent laboratory "weed" and they can contaminate other cell cultures in the same laboratory, interfering with biological research. The degree of HeLa cell contamination among other cell types is unknown, because few researchers test the identity or purity of already-established cell lines. It has been demonstrated that a substantial fraction of in vitro cell lines - approximately 10%, maybe 20%, are actually HeLa cells, due to the fact that the original cells in the cell culture have been overwhelmed by a rapidly growing population derived from HeLa contaminant cells. Stanley Gartler in 1967 and Walter Nelson-Rees in 1975 were the first to publish on the contamination of various cell lines by HeLa."

And recently the TE-7 which have been used for over 20 years as an esophageal cancer model, were found to be a completely different cancer. This has led to the proposal that all cell lines be continuously tested:

"He said the best way to get scientists to comply would be to withhold research grants and publication in scientific journals unless their research used authenticated cell-lines. This verification can be achieved using a technique of DNA profiling which compares the cell-line with a list of known contaminants and can cost as little as £180 per sample. "

Paranoid or justified?