Activating mutations in the kinase domain of epidermal growth factor receptor (EGFR) are present in about 10% to 40% of NSCLC patients, most frequently in-frame deletions in exon 19 (ex19 del) and a missense arginine-to-leucine mutation at codon 858 (L858R) (Sharma et al., 2007; Pao and Chmielecki, 2010). The gene discussed is EGFR; the disease is non-small cell lung carcinoma.