EGFR and lung carcinoma: Gefitinib (IressaTM, ZD‐1839) was the first EGFR TKIs approved by the FDA in 2003, which was used as the first line of treatment for lung cancer with mutated EGFR.[139, 140] The N quinazoline ring of gefitinib forms a hydrogen bond with Met793 in the hinge region of EGFR.