Tyrosine kinase inhibitors, such as erlotinib, have been developed and approved for use in maintenance (i.e., after platinum-based first-line treatment without progression) and second-line treatment of NSCLC [2], [3].  Approximately 10-20% of NSCLC tumors have a somatic mutation in EGFR, but prevalence varies among patients with different phenotypes (e.g., women, Asians, non-smokers versus smokers, cancer histology). The gene discussed is EGFR; the disease is non-small cell lung carcinoma.