STAT3-addicted cancer cells can develop a switch towards aerobic glycolysis program through two mechanisms: a) the up-regulation of HIF-1α, which in turn mediates the induction of several glycolytic genes [e.g., hexokinase 2, LDH-A, pyruvate dehydrogenase kinase 1 (PDH), PKM2] (136); and b) the down-regulation of mitochondrial activity, which is totally or partially independent of HIF-1α. The gene discussed is HIF1A; the disease is cancer.