EGFR and non-small cell lung carcinoma: Small molecule inhibitors that block binding of adenosine-5′-triphosphate (ATP) to the tyrosine kinase catalytic domain have been developed, and gefitinib and erlotinib are the first generation of such agents, which act as tyrosine kinase inhibitors (TKI) at the EGFR. In 2004, three groups of researchers reported that activating mutations of EGFR detected by direct sequencing were present in a subset of NSCLC and that tumors with EGFR mutations were highly sensitive to EGFR-TKI [1–3].