STAT3 and non-small cell lung carcinoma: Li et al. (2014) also reported on the effects of metformin in inhibiting the IL-6/STAT3 signaling pathway, reversing epithelial–mesenchymal transition (EMT), and overcoming EGFR-TKI drug (gefitinib and erlotinib) resistance in NSCLC cells. However, most relevant studies have been conducted in vitro and in vivo, and the mechanisms are still unclear.