Xenotropic murine leukemia virus-related virus (XMRV) is a gammaretrovirus. The virus was first described in 2006 and has since been isolated from human biological samples. XMRV belongs to the family Retroviridae and the genus gammaretrovirus. It has a single-stranded RNA genome that replicates through a DNA intermediate. The virus gets its name due to its close relationship with the murine leukemia viruses (MuLVs). The viral genome is approximately 8100 nucleotides in length and is 95% identical with several endogenous retroviruses of mice. While gammaretroviruses have well-characterized oncogenic effects in animals, they have not been shown to cause human cancers. However, XMRV was recently discovered in human prostate cancers and is the first gammaretrovirus known to infect humans. In addition to prostate cancer, a possible association with chronic fatigue syndrome has been reported, however it has yet to be established whether XMRV is a cause of this disease.

The causal role of XMRV in cancer has yet to be established and the virus does not appear to be capable of transforming cells directly. In prostate cancer, XMRV protein has been found in tumour-associated but nonmalignant stromal cells, but not in the actual prostate cancer cells. This raises the possibility that the virus may support tumorigenesis. In other studies, XMRV proteins and nucleic acids were found in malignant cells.

For research use only and NOT intended for in vitro diagnostics.