Lung cancer, of which non-small-cell lung cancer (NSCLC) is the most common form, remains the leading cause of cancer-related deaths worldwide.1 Currently, gefitinib, as the first epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor (TKI), is one of the most accepted therapies against NSCLC carrying EGFR mutations. The gene discussed is EGFR; the disease is cancer.