Together with the findings that overexpression of MYC in the mouse prostate causes PIN [1], [32] that progresses to adenocarcinoma[1], and that MYC can transform isolated human prostate epithelial cells into tumorigenic cells when mixed with urogenital sinus mesenchyme [33], these results suggest MYC overexpression may also be a critical factor contributing to prostatic adenocarcinoma initiation. This evidence concerns the gene MYC and prostate intraepithelial neoplasia.