EGFR and non-small cell lung carcinoma: When chemotherapy is no longer effective, some targeted medicines such as gefitinib (an epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor (TKI)) can be used for advanced NSCLC patients with EGFR mutations (deletions in exon 19 and L858R in exon 21) to further prolong patient survival [5].