Among somatic mutations in the EGFR kinase domain including, deletions in exon 19 (Ex19Del), insertions in exon 20 (Ex20Ins) and point mutations L858R, T790M, G719X and L861Q, L858R in exon 21 is the widespread oncogenic mutation in this domain in patients with EGFR-mutated NSCLC [2, 3, 10, 13]. Here, EGFR is linked to non-small cell lung carcinoma.