EGFR sensitive mutations, especially in-frame deletions in exon 19 and a point mutation in exon 21 (L858R), are present in 30–40% of non-small cell lung cancer (NSCLC) patients and respond well to EGFR-TKIs such as gefitinib and erlotinib. This evidence concerns the gene EGFR and non-small cell lung carcinoma.