Hypoxia is a potent inducer of HIF1α, but it did not appear to be necessary for KLF5 loss to induce HIF1α, at least in cancer cell lines, because the morphological and molecular alterations in PC-3 and DU 145 cells were detected under normoxic conditions (Figures 4, 5 and 6). The gene discussed is KLF5; the disease is cancer.