ROS generated under hypoxic conditions induce PGP and BCRP expression through HIF-1α and increase cancer cell drug resistance.358 HIF-1α induces multidrug resistance-associated protein 1 (MRP1) expressions and enhances drug resistance in colon cancer cells.359 Moreover, HIF-1α enhances the inactivation of chemotherapeutic drugs and reduces their cytotoxic effects. This evidence concerns the gene ABCC1 and colonic neoplasm.