U.S. Food and Drug Administration (FDA) approved afatinib for patients with metastatic non-small cell lung cancer whose tumors express EGFR exon 19 deletions or exon 21 (L858R) substitution mutations as well as the patients with advanced squamous cell lung cancer who have progressed after treatment with platinum-based chemotherapy [15]. The gene discussed is EGFR; the disease is squamous cell lung carcinoma.