Non-small cell lung cancers (NSCLCs) that harbour activating mutations and/or amplification of the EGFR locus are particularly sensitive to EGFR-tyrosine kinase inhibitors (TKIs) such as gefitinib (Iressa; AstraZeneca International) and erlotinib (Tarceva; OSI Pharmaceuticals) [3]–[9]. The gene discussed is EGFR; the disease is non-small cell lung carcinoma.