Medical newsgroups are reporting a finding with potentially major implications for identifying a viral cause of prostate cancer. The report states that researchers at the University of Utah and Columbia University medical schools have discovered a type of virus known to cause leukemia and sarcomas in animals and has been found for the first time in malignant human prostate cancer cells.
A team of researchers, led by senior study author Dr. Ila R. Singh, an associate professor of pathology at the University of Utah, studied 200 samples of prostate cancer cells and then compared them with 100 samples of healthy prostate cells.
Singh and his team discovered that the XMRV virus (Xenotropic murine leukemia virus-related virus) was present in 44% of tumors that received measure of a 9-10 point Gleason severity scale. The scale measures aggressiveness of prostate cancers, with lower ratings associated with having a normal prostate.
Discussions on newsgroups reveal that XMRV has been under investigation for its potential role in causing cancer for some time. The 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.
XMRV is a retrovirus like HIV and it works by making a replica of its own DNA into chromosomes of a cell they infect. Proteins from the virus were found nearly entirely in the malignant cells, which indicate an association between being infected with the virus and developing tumors. The virus XMRV was previously known to cause leukemia in animals, but has now been connected to human prostate cancer, indicating that the disease could have a viral origin.
Posts on these medicine related newsgroups relay that this is the first time researchers have given strong evidence that a virus known to cause cancer in animals is linked to prostate cancer in humans.
Approximately 1 in 4 prostate cancers tested contained the XMRV virus, compared to only 6 per cent of cancer-free tissues. Prostate cancer is the second most common cancer among men in the U.S. behind skin cancer. According to the National Academy of Sciences, 190 thousand men have received a diagnosis of prostate cancer this year in the United States. If further research shows that XMRV causes prostate cancer in males, it could assist in making diagnostic tests, vaccines and therapies for treating the cancer.