Prostate Cancer Caused By a Virus?

Researchers reporting online in yesterday's Proceedings of the National Academy of Sciences think prostate cancer may be related to a virus. Scientists at Columbia University and the University of Utah have determined that a virus that's already known to cause certain other cancers in animals is present in human prostate cancer cells.

Comparing more than 200 human prostate cancers to more than 100 non-cancerous prostate-tissue samples, they found that 27 percent of the cancers contained the virus known as XMRV, which was found in only 6 percent of the benign tissues. XMRV has been under investigation for its potential role in causing cancer for some time; this new study strengthens the link and also dispels the previous belief that certain people with genetic mutations are more susceptible than others the XMRV infection.

There's no evidence yet that XMRV causes prostate cancer. But should such a relationship emerge, the discovery might lead to new ways to diagnose, treat or even prevent the disease, which affects nearly 200,000 men each year in the U.S.

Other viruses are known to cause cancer in humans. For instance, the human papillomavirus, or HPV, causes cervical cancer in women. The Gardasil vaccine targets HPV and thus wards off that form of cancer.

A prostate cancer vaccine is still a distant prospect, though. And researchers point out that much remains to be learned about XMRV. Does it affect women? Is it sexually transmitted? How common is it? And does it cause cancer elsewhere in the body, other than in the prostate?

"We have many questions right now," said lead researcher Ila Singh of the University of Utah in a press release, "and we believe this merits further investigation."