One of the most pivotal interactions in both human and murine prostate cancer is that between PTEN and the ETS-related gene, ERG. Genomic alterations of ERG resulting from a fusion with the androgen responsive trans-membrane protease, serine 2 (TMPRSS2) gene are highly pervasive in prostate cancer and can be detected in about 40–70% of clinically significant diseases. This evidence concerns the gene ERG and prostate cancer.