In nonsmall cell lung cancer (NSCLC), EGFR mutations cluster around the tyrosine kinase domain (ATP-binding pocket; exons 18–21) and some of these mutations are associated with increased sensitivity to EGFR-tyrosine kinase inhibitors (EGFR TKIs) such as gefitinib, erlotinib, and afatinib; these drugs have been approved for treatment in advanced NSCLC with sensitive mutations [18–23]. Here, EGFR is linked to lung cancer.