Among most patients with NSCLC who harbor EGFR-activating mutations, such as deletions in exon 19 (19del) and the L858R mutation, a high initial response rate is observed when treated with first-generation EGFR-TKIs, including gefitinib, erlotinib, and icotinib [38]. The gene discussed is EGFR; the disease is non-small cell lung carcinoma.