EGFR and lung cancer: Lung cancer is the most common cancer and the leading cause of cancer-related death, and non-small cell lung cancer (NSCLC) accounts for 84% of all lung cancer diagnoses.1 Epidermal growth factor receptor (EGFR) is often overexpressed in NSCLC.2 EGFR tyrosine kinase inhibitors (TKIs) have been widely used to treat EGFR-positive NSCLC.