To explore the potential mechanism of AMPK activation downregulating H3K9me2, the H3K9me2 histone modifiers (G9a, PHF2, PHF8, JMJD2A, KDM4B)27–31 that reported to play a regulatory role in cancer pathogenesis were respectively performed co-immunoprecipitation with AMPKα2. The gene discussed is PRKAA2; the disease is cancer.