DNA profiling of dozens of ovarian and endometrial cell lines collected from multiple institutions found significant rates of misidentification, contamination, and redundancy among the samples.
Christopher Korch, PhD, doesn't like being the bearer of bad news.
The director of the University of Colorado Cancer Center's DNA Sequencing and Analysis Service recently analyzed a cell line that a researcher thought was endometrial cancer only to discover that it was actually breast cancer. The news forced the researcher to halt publication of a study in which he had used the misidentified cells. “It's hard to tell someone that their conclusions may be flawed and that they've lost 6 months', a year's, or a decade's worth of work,” says Korch.
Unfortunately, such conversations aren't rare, says Korch. He and his colleagues recently published a study in Gynecologic Oncology that used DNA profiling to analyze dozens of ovarian and endometrial cell lines collected from multiple institutions in the United States, Europe, and Japan. They found significant rates of misidentification, contamination, and redundancy among the samples.
Among 51 samples purportedly from ovarian cancer cell lines, the researchers identified 8 as existing breast cancer, teratocarcinoma, or cervical cancer cell lines; 10 were redundant cell lines. Two supposedly normal endometrial cell lines were genotyped and found to be HeLa cervical carcinoma cells and MCF-7 breast cancer cells.
The new study adds to evidence compiled over several years showing that 18% to 50% of cell lines used in biomedical research, including cancer research, are misidentified, contaminated, or redundant.
Samples that are mislabeled and then shared aren't the only cause of identity problems. Equipment could be improperly sterilized or two researchers could be working with different cultures in the same hood, explains Korch. Also, cells can travel in aerosols, landing where they shouldn't, and survive. “HeLa grows well and can out-compete if they get into the culture of a slow-grower,” he says.
The American Type Culture Collection, a nonprofit biologic resource center based in Manassas, VA, released voluntary guidelines in January calling for the routine authentication of cell lines with short tandem repeat (STR) profiling. Widely available, STR profiling takes about a week and costs $100 to $200 per sample.
“It's the equivalent of about 20 lattes to profile a cell line and know whether what you have is what you want,” says Korch. “Is that too much to spend? Well, I'd rather be sure.
For more news on cancer research, visit Cancer Discovery online at http://CDnews.aacrjournals.org.