Studies' results released on Friday discovered a virus in the prostate of cancer patients with a particular genetic mutation which may have a role in causing the illness. The virus was found in prostates affected by cancer, removed from men with a certain genetic defect. The researchers from the University of California, San Francisco, and the Cleveland Clinic, state that no specific link was found between the virus and prostate cancer, but they are hopeful for future research. Dr. Eric Klein of the Cleveland Clinic said at the conference where the results were presented: "We have made a very fascinating discovery never before seen in humans that is very similar to one found in a mammal that causes cancer, but we have not proven this virus causes prostate cancer." Still, "there is now a suggestion that prostate cancer could be caused by an infectious disease." The studies say the gene mutated in some men is important in the body's defense system, which helps kill invading viruses; men with the genetic mutation produce fewer of these defense cells, showing that genetics plays an important role in the viral connection with cancer. Viruses which cause infectious disease are already linked to liver and cervical cancers. Researchers said that they will test more prostates and that they are developing a tool which will search for the virus in the blood. Also, they want to see how common is the virus and whether it is exclusive to patients suffering from prostate diseases. Links will be studied between the virus and genetic and racial backgrounds. Prostate cancer is the most common cancer in America and the second cause of death for men over 50. Preliminary studies show that this type of cancer is found more often among black and overweight people.