EGLN1 and cancer: Under physiological conditions, HIF-1α can be quickly hydroxylated and degraded by PHD2; however, multiple factors involved in TAM may modulate PHD2 activity to inhibit HIF-1α degradation, leading to the maintenance of HIF-1α protein, and promote aerobic glycolysis in cancer cells (Hsu and Sabatini, 2008; Semenza, 2012; Semenza, 2013).