In metabolic coupling, PSCs tend to undergo glycolysis by taking up glucose and secreting lactate, with up‐regulated expression of glycolytic enzymes (HK‐2, PFKP and PKM2) and the transporter enzyme MCT4, and down‐regulated expression of OXPHOS enzymes (TOMM20, NQO1) and the transporter enzyme MCT1; cancer cells tend to undergo OXPHOS by taking up lactate, with down‐regulated expression of glycolytic enzymes (HK‐2, PFKP and PKM2) and the transporter enzyme MCT4 and up‐regulated expression of OXPHOS enzymes (TOMM20 and NQO1) and the transporter enzyme MCT1 (Figure 6). The gene discussed is PKM; the disease is cancer.