EGFR and non-small cell lung carcinoma: EGFR tyrosine kinase inhibitors (TKIs) have revolutionized the treatment of patients with NSCLC harboring EGFR mutations, especially sensitizing EGFR mutations such as exon 19 deletions (19del) and exon 21 L858R point mutations (L858R).2, 3, 4, 5, 6, 7 These common somatic mutations account for approximately 85% of EGFR gene alterations.8