To further dissect the tumour promoting effects of loss of Stat3, we established primary mouse Pten−/− PCa cells with stable, short hairpin RNA (shRNA) mediated knockdown of Stat3. Western blot and IHC analyses confirmed efficient Stat3 knockdown in these cells (Fig. 3a and Supplementary Fig. 4a). The gene discussed is PTEN; the disease is posterior cortical atrophy.