EGFR mutations have been found in fewer than 10% of non-Asian patients with NSCLC,[5] and in 30% of East Asians’ patients.[6] Missense mutations in exon 21 (L858R) and in-frame deletions within exon 19 have been shown to be the most frequent EGFR-TKI sensitive mutations (80%) in NSCLC.[7] Both exon 19 deletion and exon 21 missense mutations are common EGFR mutations and have been proved to be associated with a favorable response to first-line treatment with gefitinib[8] as well as other EGFR-TKIs such as erlotinib[9] and afatinib[10] compared with standard chemotherapy in patients with NSCLC. This evidence concerns the gene EGFR and non-small cell lung carcinoma.