APEX1 and cancer: The redox regulators that govern the activity of antioxidant enzymes in cancer cells include nuclear factor erythroid‐2‐related factor 2 (Nrf2), ataxia telangiectasia‐mutated (ATM), forkhead homeobox type O family (FoxOs), and apurinic/apyrimidinic endonuclease 1/redox factor‐1 (APE1 Ref‐1).