EGFR and lung adenocarcinoma: Among the receptor TKIs, single-agent erlotinib (Tarceva, Genentech, Inc, South San Francisco, CA, USA and OSI Pharmaceuticals Inc., Melville, NY, USA) improves survival in advanced NSCLC patients who progressed after chemotherapy [7-10] and is superior to chemotherapy in the first-line treatment of lung adenocarcinoma with an EGFR mutation in exon 19/21 [2].