The cellular response to limited oxygen tensions is primarily via induction of the hypoxia inducible factors, HIF-1α and HIF-2α which are involved at crucial stages of embryonic development1, 2, 3, homeostasis4, 5, and cancer pathogenesis6, 7 such as sensing nutrient availability and intracellular pH, regulation of anaerobic glycolysis, modulation of the tumor microenvironment, and cell survival. Here, EPAS1 is linked to cancer.