Furthermore, loss of Stat3 promoted PCa formation in Pten heterozygous prostate tissue (Ptenpc+/−Stat3pc−/−) at 19 weeks of age, whereas Ptenpc+/−mice developed only prostatic intraepithelial neoplasia17 (PIN) (Supplementary Fig. 3a). Here, STAT3 is linked to prostate intraepithelial neoplasia.