Viral link to prostate tumors questioned
A new study conducted in Germany contradicts at least two earlier studies by finding no link between prostate tumors and a virus that had been found in some tumors. University of Utah researchers recently reported that they found traces of a virus called xenotropic murine leukemia virus-related virus, or XMRV, in more than quarter of human prostate tumors, particularly those that are most aggressive. Antibodies against the virus have also been found in as many as 95% of patients with chronic fatigue syndrome, suggesting that the mysterious virus, discovered only three years ago, may be at the root of several diseases of unknown etiology.
German researchers led by Dr. Reinhard Kurth and Dr. Norbert Bannert of the Robert Koch Institute in Berlin studied 589 prostate tumor samples collected in Germany. They reported today in the journal Retrovirology that they found no traces of the virus in any of the samples. Bannert suggested that "a possible geographic restriction of XMRV and its association with prostate cancer should be studied closely" -- in other words, that it may cause the disease in some places but not in others.
Dr. Robert Silverman of the Cleveland Clinic Lerner Research Institute, who originally discovered the virus, noted that the techniques used in Germany to look for the virus "are significantly different from the methods we use.... It is possible that the methods used may have missed detecting XMRV." Other possibilities are that the strain of the virus that predominates in Europe has a slightly different RNA sequence than that in the United States, he said, or simply that XMRV is more prevalent in the U.S. than in Germany.
Clearly, much more work needs to be done before anything definitive can be said about the virus's role in prostate cancer.
-- Thomas H. Maugh II