MAPK8 and fibrosarcoma: Rat sarcoma (RAS)/rapidly accelerated fibrosarcoma, (RAF)/mitogen-activated protein kinase (MEK)/extracellular signal-regulated kinase (ERK), and mitogen-activated protein kinase kinase kinase (MAP3K)/c-Jun N-terminal kinase (JNK) pathways mediate pyruvate kinase M2 (PKM2) phosphorylation, ultimately promoting glycolysis.