PDK1 and neoplasm: Lactate and hypoxia-stimulated HIF- 1α or WNT/β-catenin signaling prevent pyruvate from entering the TCA cycle and converting to acetyl-CoA by upregulating pyruvate dehydrogenase kinase 1 (PDK1) and then inhibiting pyruvate dehydrogenase complex (PDH), and drive tumor cells to obtain energy by leading to aerobic glycolysis (Kim et al., 2006; Vallee et al., 2017).