Second, although stratification analysis was performed based specifically on treatment type (EGFR-TKI therapy) and comorbidity of diabetes mellitus and strongly indicated a significant relationship between metformin use and better outcomes for diabetic and EGFR-TKI-treated NSCLC patients, only 1808 patients from three cohort studies were enrolled (Chen et al., 2015; Hung et al., 2019; Han et al., 2021) in this group. The gene discussed is EGFR; the disease is diabetes mellitus.