MicrobeWorld

The retrovirus XMRV arose during passage of a human prostate tumor in nude mice. The genomes of these mice contain two different proviral DNAs related to XMRV, pre-XMRV-1 and pre-XMRV-2, that recombined to produce XMRV that has been isolated from humans. Two other prostate cancer cell lines also contain mouse gammaretroviruses that are not XMRV. These viruses may have entered the prostate tumor cells during xenograft passage in immunocompromised mice.