(Admins: if this has been posted already please delete.) from: http://www.ncbi.nlm.nih.gov/pubmed/20717743 Immunol Res. 2010 Aug 18. [Epub ahead of print] Biology and pathophysiology of the new human retrovirus XMRV and its association with human disease. Rusmevichientong A, Chow SA. Department of Molecular and Medical Pharmacology, Molecular Biology Institute, 650 Charles E. Young Dr, CHS 23-133, Los Angeles, CA, 90095, USA. Abstract Xenotropic murine leukemia virus-related virus (XMRV) is a new human retrovirus originally identified in prostate cancer patients with a deficiency in the antiviral enzyme RNase L. XMRV has been detected with varying frequencies in cases of prostate cancer and chronic fatigue syndrome (CFS), as well as in a small proportion of healthy individuals. An etiologic link between XMRV infection and human disease, however, has yet to be established. Here, we summarize existing knowledge regarding the characteristics of XMRV replication, association of XMRV with prostate cancer and CFS, and potential mechanisms of XMRV pathophysiology. We also highlight several areas, such as the establishment of standardized assays and the development of animal models, as future directions to advance our current understanding of XMRV and its relevance to human disease.