A once-promising discovery linking prostate cancer to xenotropic murine leukemia virus-related virus was the result of an inadvertent laboratory contamination, according to a forensic analysis of tissue samples and lab experiments, some of which date back nearly a decade.
The connection was proposed more than six years ago, when the telltale signature of XMRV was detected in genetic material derived from tissue samples taken from men with prostate cancer.
Later studies failed to find the same signature, with researchers stating XMRV is an infection of human prostate cancer cells in laboratories and not of prostate cancer patients.
A new analysis by researchers from the University of California, San Francisco, Cleveland Clinic and Abbott uncovered the story behind the contamination. The original association between XMRV and prostate cancer resulted from traces of XMRV that apparently found their way into the prostate samples from other cells being handled in the same laboratory in 2003. These cells also were contaminated with the retrovirus.
“Everything arose from this presumed contamination event,” Charles Chiu, MD, PhD, an assistant professor of laboratory medicine at UCSF and director of the UCSF-Abbott Viral Diagnostics and Discovery Center, said in a news release.
When the prostate connection first emerged, Chiu said, there was a lot of excitement in the field because of the link between human papillomavirus and cervical cancer. HPV made clear that a cancer caused by a virus could be prevented by vaccination.
“Our findings do not support any association between XMRV infection and prostate cancer, and by extension indicate that XMRV has never replicated outside of the laboratory setting,” the authors concluded.
The recent news about prostate cancer and XMRV came out the same day as a report debunking the theory that XMRV and polytropic murine leukemia virus play a role in chronic fatigue syndrome (www.nurse.com/Article/CFSVirusLink).
The prostate cancer study appeared Sept. 18 in the online journal PLoS One. To read it, visit www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0044954.