EGFR and adenocarcinoma: For example, pemetrexed, which was approved in 2004 for advanced NSCLC independent of the histological type5 and was subsequently revised for second‐line indications, is now an option only for adenocarcinoma (ACC) patients.2 The development of epidermal growth factor receptor tyrosine kinase inhibitors (EGFR TKIs) has progressed significantly, and many novel EGFR TKIs have been developed.