Is XMRV a causal virus for prostate cancer?

The potential association between xenotropic murine leukaemia virus-related gammaretrovirus (XMRV) and prostate cancer (PCa) has been documented since 2006. It is important for furthering our understanding of the biological mechanisms of PCa to ascertain whether this association is causal. To summarize the available information on the epidemiological and laboratory findings of the association, we conducted a literature search of the PubMed electronic database (from March 2006 to February 2011) to identify relevant published studies that examined the association between XMRV and PCa. Although several studies showed the positive association between XMRV and PCa, more recent studies did not support this conclusion. The positive findings might be due to contamination of human samples. Further studies are needed to clarify this association.