We show that treatment of Pten(i)pe−/− mice at 3 and 10 months AGI with PX-478 elicits profound antitumor effects, including the induction of apoptosis in early PIN lesions, and a decrease in the proliferation of late ones, which phenocopies the effects of combined inactivation of Pten and Hif1a in luminal cells. This evidence concerns the gene PTEN and prostate intraepithelial neoplasia.