PKM and cancer: HIF-1α renders cancer cells more efficient in mobilizing the residual glucose strengthening glucose transporters (GLUT1 and 3), and stimulates gene transcription of several proteins involved in glucose metabolism, such as aldolase A, enolase-1, esokinase 1 and 3, lactate dehydrogenase A (LDH-A), phosphofructokinase-1 (PFK-1) and PKM2.