While knocking-down endogenous TMPRSS2/ERG in the VCaP prostate-derived cancer cells resulted in a reduction of both tumor uptake and volume [13], [14], transgenic mice harboring TMPRSS2/ERG in their genome either developed PIN [10], [15] or reveal no histological evidence of PIN or invasive cancer [11], [16]; depending on the specific model used in the study and the interpretation of the data. This evidence concerns the gene TMPRSS2 and prostate intraepithelial neoplasia.