EGFR and lung cancer: Passive smoking is also considered to be a risk factor for lung cancer,31 and an association has been clearly identified for ADC incidence (HR 2.03; 95% CI, 1.07–3.86).32 It is necessary to monitor trends in ADC and investigate the association between smoking and ADC incidence, with consideration of various factors, such as different distributions of EGFR mutations between ethnicities, smoking patterns, and genders.