Recent studies have indicated that metformin may sensitize cancer cells to chemotherapy agents in lung cancer.20, 21 For example, metformin and EGFR‐TKI have a synergistic effect in treating NSCLC patients with diabetes mellitus type 2.22 Moreover, metformin can reverse crizotinib resistance by inhibiting type I insulin‐like growth factor receptor (IGF‐1R) signalling in crizotinib‐resistant human lung cancer cells.23 Metformin and sorafenib can synergistically inhibit tumour growth by activating the AMPK pathway in NSCLC cells both in vitro and in vivo. Here, EGFR is linked to lung carcinoma.