Lung cancer is the leading cause of cancer‐related mortality worldwide, with a five‐year survival rate of less than 20%.1, 2 However, with the introduction of epidermal growth factor receptor‐tyrosine kinase inhibitor (EGFR‐TKI) treatment, lung cancer mortality has markedly improved in comparison with that of cytotoxic chemotherapy.3, 4, 5 In Korea, the incidence and survival outcome of lung cancer has changed over time in a manner similar to that of other countries.6, 7, 8. This evidence concerns the gene EGFR and cancer.