HK1 and cancer: Hypoxia-inducible factor 1 (HIF-1) is a key regulator of the metabolic reprogramming in hypoxic cancer cells through the regulation of genes such as the glucose transporters GLUT1 and GLUT3, hexokinase 1 and 2 (HK1 and HK2), and phosphoglycerate kinase 1 (PGK1), finally orchestrating the metabolic changes necessary to adapt to oxygen deprivation [56].