EGFR and non-small cell lung carcinoma: In NSCLC, EGFR mutations are limited to the first four exons (exons 18–21) of the tyrosine kinase domain, which encode the N-lobe and the 5′ portion of the C-lobe of EGFR; they consist of three different types of mutations (deletions, insertions, and missense point mutations), and they all cluster around the ATP binding pocket of the TKD of EGFR [16,17].