EGFR and neoplasm: Classically, EGFR belongs to the ERBB family of cell-surface tyrosine kinase receptors.[22] EGFR is mutated in about 16% tumor specimens from patients with NSCLC.[23] There are several described mutations in the EGFR gene, in which the 2 most common are short in-frame deletions around the LREA motif of exon 19 (45%–50%) and a point mutation (CTG to CGG) in exon 21, resulting in substitution of leucine by arginine at codon 858, L858R (45%–50%).[24] Differences between the subtypes of EGFR-mutated genes result in the discrepancy of the coding protein and the diversity of targeted treatment.