Epidermal growth factor receptor (EGFR) activating mutations, such as exon 19 deletion and exon 21 L858R point mutation, are found in a population of NSCLC, and are associated with a clinical response to the EGFR tyrosine kinase inhibitors (EGF-TKIs), gefitinib and erlotinib [1]–[3]. The gene discussed is EGFR; the disease is non-small cell lung carcinoma.