The era of molecular targeted therapy in lung cancer had its origin in 2004, when activating mutations in the epidermal growth factor receptor (EGFR) and their correlation with clinical response to EGFR tyrosine kinase inhibitors (TKIs) were discovered (Lynch et al., 2004; Paez et al., 2004; Pao et al., 2004). The gene discussed is EGFR; the disease is lung cancer.