Prostate tumors in Ptenpc−/−; Trp53pc−/− mice developed microinvasion with cells in atypical nucleus, while age-matched Ptenpc−/−; Trp53pc−/−; Skp2−/− mice showed the less severe abnormality of prostate glands with PIN lesions (Supplementary Figure S1C). This evidence concerns the gene SKP2 and prostate intraepithelial neoplasia.