Xenotropic murine leukemia virus-like virus (XMRV) was discovered in 2006 during a search for viral sequences in prostate cancer tissues. The results of a recent study revealed that the virus is present in 23% of prostate cancers from patients in the US. Understanding the role of XMRV in prostate cancers requires more extensive epidemiological studies, including the examination of tissues from patients in other countries. The prevalence of XMRV in prostate cancers from German subjects has now been assessed.
Prostate tissue samples were collected from 589 patients undergoing prostatectomy at the UniversitÃ¤tsmedizin Berlin. DNA was extracted from the biopsy material, and polymerase chain reaction (PCR) was used to detect the presence of XMRV. None of the samples were found to contain viral DNA. Furthermore, no antibodies to XMRV were detected in serum from 146 prostate cancer patients.
Two other studies have addressed the prevalence of XMRV in Germany and Ireland. In the German study, one of 105 samples from patients with prostate cancer was found to contain viral DNA. In the Irish study, no XMRV sequences were detected in 139 patient samples.
There are at least three ways to explain the results of the most recent German study. The trivial explanation is that the assay methods were not sufficiently sensitive to detect XMRV nucleic acid or antibodies. If I were working on the German samples, I would ask the authors of the American study to examine them for XMRV using their methods. Another possibility is that XMRV is geographically restricted. Alternatively, more than one gammaretrovirus might be associated with prostate cancer, which would not have been detected by the methods used by the German group.
Even after three years of research, the relationship between XMRV and prostate cancer is not understood. As Ila Singh has said, “We still don’t know that this virus causes cancer in people, but that is an important question we’re going to investigate.”
Hohn O, Krause H, Barbarotto P, Niederstadt L, Beimforde N, Denner J, Miller K, Kurth R, & Bannert N (2009). Lack of evidence for xenotropic murine leukemia virus-related virus (XMRV) in German prostate cancer patients. Retrovirology, 6 (1) PMID: 19835577