Mutations in the epidermal growth factor receptor (EGFR) gene are common in lung adenocarcinoma, with an estimated prevalence in lung adenocarcinoma of 23% (range, 3–42%) in the United States (US) and greater frequency in Asian than non-Asian patients, in women than men, and in never-smokers (vs. smokers) (2, 3). The gene discussed is EGFR; the disease is lung adenocarcinoma.