IHC analysis reveals that strong SKP2 positive staining was mainly observed at the sites of prostatic lesions (i.e. hyperplasia, PINs and low-grade carcinoma), accompanied by decreased staining intensities of p27Kip1 in probasin-hSKP2-KI mice compared to those from wild-type mice (Fig. 3A). This evidence concerns the gene CDKN1B and hyperplasia.