SLC2A1 and neoplasm: HIF-1 activation in tumor cells up-regulates the expression of some glycolytic enzymes and transporters, including 6-phosphofructo-2-kinase/fructose-2,6-biphosphatase 3 (PFKFB3), M2 isoform of pyruvate kinase (PKM2), and glucose transporter 1 and 3 (GLUT1, GLUT3) [71].