Metformin, an AMPK agonist, is gradually emerging as a repurposed anticancer agent.20,21 A few clinical trials have also identified that metformin improves the progression-free survival and distant metastasis-free survival in lung cancer patients, but the underlying mechanisms remain elusive.22–24 We hypothesized that metformin treatment would inhibit lung cancer metastasis via AMPK activation. The gene discussed is PRKAA2; the disease is lung carcinoma.