"I don't know yet if this is the better test, but it might be linked to more aggressive prostate cancers," Singh speculated.
Robert A. Silverman, a professor of cancer biology at the Cleveland Clinic, was one of the researchers who first reported the association of XMRV with prostate cancer. He called the new study "very exciting."
"Finding it in cancer cells makes it easier to reconcile with the idea of a cancer-causing virus than in our prior study," Silverman said. "The prior study found the virus in cells surrounding the cancer. We can't say with certainty that XMRV is a cause of cancer, but it still is a candidate for a cancer-causing virus."
Even if causation is not proved, "XMRV could be a marker for aggressive tumors," Silverman said.
His group has continued research on the virus, one of which indicates that human semen promotes the activity of XMRV, Silverman said.
The new study also overturns a previously reported association between XMRV infection and a genetic variation carried by a small percentage of men. "We don't find any such association," Singh said. So, the new research appears to expands the population at risk from the virus to all men -- whether they carry the genetic variant or not.
Singh and her colleagues are expanding their research on XMRV. "We don't know if women have the virus, and we are looking at cervical cells from Pap smears," she said. "We are looking at seminal fluid from men and also at tissues other than the prostate. We have two large series of autopsies of male and female organs. We are also looking for antibodies to the virus in serum as a way to detect infection."
Find out more about prostate cancer at the U.S. National Cancer Institute.
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