AMPK is activated by serine/threonine kinase LKB1, a major kinase phosphorylating AMPK under conditions of energy stress.17 Metformin is known to trigger its activation through LKB1‐dependent phosphorylation of AMPK under conditions of low intracellular ATP.18 LKB1 is inactivated by somatic mutation in approximately 30% of NSCLCs.19 However, the molecular mechanism involved in the antitumour effect of metformin that is dependent on LKB1 status remains unclear in NSCLC cells. Here, STK11 is linked to non-small cell lung carcinoma.