ARNT and cancer: Hypoxia is generally caused by excessive oxygen consumption and insufficient oxygen/glucose supply, and hypoxic cancer cells have been recognized as more resistant to chemotherapy.44 Inadequate oxygen supply could induce cancer cells to initiate a complex phenotype transformation such as hypoxia inducible factor‐1 (HIF‐1), which acts as the master regulator of hypoxia.45 The HIF‐1 is a heterodimer comprised of HIF‐1α and HIF‐1β subunits, and it is regulated by oxygen concentrations.