HK1 and cancer: PKM2 is regarded as one of the major oncogenic glycolytic enzymes and is abundantly expressed in numerous highly proliferative cells such as cancer cells.12,14,15,30–33 Although phosphoglycerate kinase is another ATP-generating enzyme, this enzyme is the first step of the “pay off” phase of glycolysis, which follows the preparatory steps of glycolysis (hexokinase (HK) and phosphofructokinase-1 (PFK1)), which consume ATP and therefore does not produce any net ATP.