HK2 and cancer: Increasing evidence in different cancers indicates that TGF-β promotes glycolysis while inducing EMT and upregulates the expression of several glycolytic metabolic enzymes, such as glucose transporter 1 (GLUT1), hexokinase 2 (HK2), 6-phosphofructo-2-kinase/fructose-2,6-biphosphatase 3 (PFKFB3), and pyruvate kinase M2 (PKM2) [18,19,20,21].