Asian Pac J Cancer Prev, 14 (11), 6929-6933 IntroductionProstate cancer is the most common malignancy in men worldwide (Groom et al., 2012). The annual incidence rates of prostate cancer among Iranian population are dramatically higher than in other countries of Asia (Akbari et al., 2008). Multiple etiologies have been hypothesized for the cause of prostate cancers, including genetic defects, infectious agents and associated inflammation (Silverman et al., 2010). Identification of a potential virus as the cause of prostate cancer is very important because it could facilitate management of this disease such as treatment and prevention. A recently described retrovirus, the xenotropic murine leukemia virus-related virus (XMRV) was detected in about 40% of familial prostate cancer using a DNA microarray (Virochip) containing oligonucleotides comprising conserved sequences from known viral genomes and was strongly associated with homozygosity for the R462Q reduced activity, a variant of the antiviral enzyme, RNase L (Urisman et al., 2006).Murine leukemia viruses (MLVs) belong to gammaretroviruses in the retroviridae family, which viral RNA is reverse-transcribed to DNA during replication. They are endogenous viruses that have integrated their provirus DNA into the mouse genome and can cause leukemias, lymphomas, neurologic diseases, and has been reported to be detected in prostate cancer. However, this virus has not been detected in similar groups of patients in other studies. Herein, we sought to detect XMRV in prostate cancers and benign controls in Sanandaj, west of Iran. Materials and Methods: In a case-control study, genomic DNA was extracted from formalin fixed and paraffin embedded prostate tissues from a total of 163 Iranian patients. We developed a conventional and a nested PCR assay using primers targeting to an env specific sequence of XMRV. PCR assays were carried out on 63 prostate cancers and 100 benign prostate hyperplasias. Results: Beta-actin sequences were successfully detected in the DNA extracts from all prostate tissues, confirming DNA extraction integrity. We did not detect XMRV in samples either from prostate cancers or benign prostate hyperplasias using XMRV specific primers. Conclusions: We conclude that in our population XMRV does not play a role in genesis of prostate cancer.