EGFR and lung cancer: 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.