HIF1A and prostate intraepithelial neoplasia: However, the time-dependent emergence of the stromal reaction in Pten(i)pe−/− prostates was largely attenuated in Pten/Hif1a(i)pe−/− ones (Fig. 2, B and C), indicating that luminal HIF1A does not play a major role in PIN formation but may have an effect on microenvironmental cells.