A virus that causes cancer in animals may also be a causative factor in human prostate cancer, according to a study published by U.S. researchers. The virus, called XMRV, is a retrovirus. Previous studies have shown that this virus can cause cancer in animals, but it has not been found to cause cancer in humans as well. Researchers at the University of Utah and Columbia University School of Medicine scanned the tumors of 233 prostate cancer patients and the prostate tissue of 101 healthy people and found that the XMRV virus was present in 27 percent of prostate tumors and that the virus was present in a higher percentage of malignant tumors and would be present in only 6 percent of healthy prostate tissue. In addition, the viral protein of XMRV only binds to human proteins in prostate tumors, suggesting that infection with the XMRV virus may be directly linked to the formation of prostate tumors. The researchers said they are currently unable to determine whether the XMRV virus is a causative factor in prostate cancer, but once confirmed, the results will hopefully open up new avenues for the development of drugs or vaccines for prostate cancer treatment. The study was published in the online edition of the Journal of the National Academy of Sciences on July 7. Prostate cancer is second only to lung cancer as a common cancer in men, with about 250,000 men dying of prostate cancer each year worldwide. Currently, a variety of cancers suffered by humans are triggered by viruses, such as cervical cancer and lymphoma. Researchers in the United States have published a study showing that a virus that causes cancer in animals may also be a causative factor in human prostate cancer. The virus, called XMRV, is a retrovirus. Previous studies have shown that this virus can cause cancer in animals, but it has not been found to cause cancer in humans as well. Researchers at the University of Utah and Columbia University School of Medicine scanned the tumors of 233 prostate cancer patients and the prostate tissue of 101 healthy people and found that the XMRV virus was present in 27 percent of prostate tumors and that the virus was present in a higher percentage of malignant tumors and would be present in only 6 percent of healthy prostate tissue. In addition, the viral protein of XMRV only binds to human proteins in prostate tumors, suggesting that infection with the XMRV virus may be directly linked to the formation of prostate tumors. The researchers said they are currently unable to determine whether the XMRV virus is a causative factor in prostate cancer, but once confirmed, the results will hopefully open up new avenues for the development of drugs or vaccines for prostate cancer treatment. The study was published in the online edition of the Journal of the National Academy of Sciences on July 7. Prostate cancer is second only to lung cancer as a common cancer in men, with about 250,000 men dying of prostate cancer each year worldwide. Currently, a variety of cancers suffered by humans are triggered by viruses, such as cervical cancer and lymphoma.