HK2 and cancer: The role of HIF-1α in reprogramming cancer metabolism toward the Warburg effect depends on its transcription activity, i.e., the activation of HIF-1 pathway would enhance the transcription of glucose metabolism gene such as glucose transporter 1 (GLUT1), hexokinases2 (HK2), and lactate dehydrogenase A (LDHA) (Semenza, 2003).