Overall, the available evidence indicates that upfront EGFR mutation testing for patients with advanced NSCLC can help guide treatment decisions (i.e., EGFR mutation status can identify NSCLC patients who are more likely to respond to erlotinib, whereas those with wild-type tumors are unlikely to respond to erlotinib and alternative treatment should be considered). The gene discussed is EGFR; the disease is non-small cell lung carcinoma.