Whoops: The Case of Mistaken Cell Lines

Jacob Schor ND FABNO
September 22, 2008

In cancer research there is a long tradition of testing potential therapies on tumor cells grown in Petri dishes. If you want to know whether a new drug might be useful, say against breast cancer in women, you try it first on breast cancer cells growing in a Petri dish. The breast cancer cells used by researchers come from several well established lines originally obtained from cancer patients years ago and carefully distributed to researchers.

It’s not just chemotherapy but also nutrients and botanical extracts that go through this sort of testing on cell lines in what are called in vitro experiments. I’ve wondered about the logic in doing this. My understanding is that each cancer is unique. One woman’s breast cancer is not the same as another’s. Cancer is caused by a combination of genetic hits, changes in the DNA expression in a cell. No two cancers have the same exact combination of hits, so each cancer is considered unique. So why the fuss of using a few cell lines to study cancer when they are all so different?

What makes sense about this is not the particular cancer type that is being tested but the cell type. Cells from different tissues in the body will respond differently to treatments. Some may be more sensitive to certain chemicals or respond more strongly to certain stimuli. Obviously breast tissue will respond differently to estrogen than lung tissue. From our side of the fence where we are seeking nutrients or extracts that trigger apoptotic mechanisms in the cancer cell, it makes sense to test things on ‘sick’ cells that are related to the target tissue that has become cancerous.

Ralph moss disturbed my happy cogitations along this theme yesterday when he alerted me and his other newsletter readers of a recent article in The Scientist that turns all of these careful ruminations upside down.

Writing in the September 16th issue, Megan Sudellari points out a series of papers that strongly suggest that the breast tumor cell line known as MDA-MB-435 is probably not breast cancer. It appears to be skin cancer. Researchers have been using this cell line for the past 25 years to conduct research on breast cancer, especially breast cancer metastasis. During this time they have published over 650 papers on breast cancer, well on what they thought was breast cancer, when in fact it appears the original cells were skin cancer, malignant melanoma to be exact. As Dr. Moss points out, “Melanoma-derived tumor cells are not biologically equivalent to breast cancer cells; they have different molecular and genetic characteristics.”

This is a real shocker to say the least. So far I haven’t seen a glimmer of this in the popular press. The scientific community might not be in a hurry to send out press releases advertising their mistake. Give it time though and creative drug marketers will start suggesting Tamoxifen be used to treat skin cancer.

Dr. Moss poses the obvious question; “We are constantly being reminded that this is the era of evidence-based medicine. But if the very cell lines which have provided the foundation for breast cancer research for the past quarter century have now been conclusively shown to be melanoma cells, not breast cancer, how solid or trustworthy is the evidence on which current breast cancer treatment is based? Evidence built on such flawed foundations more closely resembles hearsay than science.”

A Case of Mistaken Identity by Megan Scudellari. The Scientist, September 16th 2008