EGFR and lung cancer: Epidermal growth factor receptor (EGFR)–tyrosine kinase inhibitor (TKI) therapy plays an important role in treating clinical stage IV EGFR (OMIM 131550) variant–positive non–small cell lung cancer (NSCLC).1,2 Previous studies3,4 have found that EGFR-TKIs, such as erlotinib, gefitinib, and icotinib, promote longer progression-free survival (PFS) in patients with EGFR variant–positive NSCLC than conventional chemotherapy.