HK2 and cancer: Cancer cells tend to utilize glycolysis rather than oxidative phosphorylation to adapt to the hypoxic tumor microenvironment (TME) and this process largely depends on the abnormally expressed glycolytic genes, such as glucose transporter 1 (GLUT1), hexokinase 2 (HK2), liver-type phosphofructokinase (PFKL), and lactate dehydrogenase A (LDHA) 6-8.