The role of AR in prostate cancer initiation is accentuated by the seminal discovery that the oncogenic ETS family transcription factors, such as ERG and ETV1, are translocated to the loci of androgen regulated genes including TMPRSS2 in approximately 50% of all human prostate cancers (Kumar-Sinha et al., 2008; Tomlins et al., 2005). This evidence concerns the gene ERG and prostate cancer.