Due to the inconsistent results of epidemiological studies, several meta-analyses were carried out and the statistical results showed that the use of metformin could improve the survival of patients with lung cancer.[28–31] In addition, various preclinical studies have found that metformin enhances the anti-tumor effects of platinum and increases their sensitivity by regulating multiple signaling pathways including AMPK-mTOR, ERK1/2, NF-κB.[32–34] Thus, we hypothesized that metformin might benefit lung cancer patients who received platinum-based chemotherapy. This evidence concerns the gene MAPK3 and lung cancer.