STK11 and non-small cell lung carcinoma: Shackelford et al. demonstrated several years ago that the drug phenformin, a biguanide chemically related to metformin, was more effective in the treatment of non-small cell lung cancer (NSCLC) if the tumors lacked a functional LKB1-AMPK pathway, suggesting an LKB1-AMPK-independent mechanism of action [45].