HK2 and osteosarcoma: In fact, it has been previously observed that EGF signaling activates the first step in glycolysis with hexokinase 2 (HK2) but impedes the last step with pyruvate kinase muscle isozyme M2 (PKM2) in triple breast cancer cells [37], and that PKM2 expression is aberrantly high in osteosarcoma tissues [38].