Depending on the strain background and splicing variants of ETS genes, some of these studies suggested that there are Prostate Intraepithelial Neoplasia (PIN)-like lesions in PB-ERG and PB-ETV1 transgenic males [4–7], whereas others indicated that PB-ERG transgenic males are normal in their prostates [3,8]. This evidence concerns the gene ETV1 and prostate intraepithelial neoplasia.