In contrast to the results obtained when Pten deletion was triggered by OHT in mice at 6 wks of age, Pten excisions induced immediately prior to the onset of puberty led to more rapid pace of disease progression, with PIN lesions already being present at 4–6 wks post-OHT (Figure 5), and high grade PIN lesions and microinvasive carcinoma developing at 10–12 wks post-OHT (Figure 5). This evidence concerns the gene PTEN and prostate intraepithelial neoplasia.