New virus discovered in prostate tumors

Researchers at the Cleveland Clinic and the University of California, San Francisco, have discovered a new virus in prostate tumors. In their study of 150 men, the team identified the XMRV virus and determined that it is 25 times more likely to be found in prostate cancer patients with a specific genetic mutation than in men without the mutation.

“This is a virus that has never been seen in humans before,” said lead author Eric Klein, MD, of the Cleveland Clinic. “This is consistent with previous epidemiologic and genetic research that has suggested that prostate cancer may result from chronic inflammation, perhaps as a response to infection.”

In the study, researchers examined tissue samples of 86 prostate cancer patients whose prostates had been surgically removed. In these samples, the Cleveland researchers determined genetic variations in the RNaseL gene, which fights viral infections, and sent the findings to UCSF scientists. Using a DNA-hunting “virus chip,” (ViroChip) they discovered the new virus far more often in human prostate tumors shown to have the RNaseL mutation than not.

Using the chip and the patient samples, researchers found the XMRV virus in eight (40%) of the 20 men with two mutated copies of the RNaseL gene and only 1.5% of the 66 men who had one copy or no copy of the mutated gene.

“While we can’t state that this virus causes prostate cancer, these are remarkable findings because of the association of the virus with the mutation,” said Robert Silverman, PhD, of the Cleveland Clinic.

The group’s findings were presented at the recent Prostate Cancer Symposium in San Francisco. Look for more details on this and other studies from this meeting in the April issue of Urology Times.