EGFR and non-small cell lung carcinoma: Several activating mutations are recognised in EGFR in NSCLC, including Class I exon 19 in-frame deletions (accounting for 44% of all EGFR mutations), Class II single amino acid changes (such as L858R accounting for 41%, G719 for 4% and other missense mutations for 6%) and Class III exon 20 in-frame duplications or insertions (constituting 5%) [10].