EGFR and lung cancer: For instance, recent studies have demonstrated that the propyl derivative of gefitinib exhibits potent cytotoxic activity against the A549 cell line (pulmonary adenocarcinoma cell line), A431 (lung cancer cell line), and MDA-MB-231 (breast cancer cell line) by inhibiting EGFR, with IC50 values of 10.23 ± 2.3 μM, 10.87 ± 0.18 μM, and 1.68 ± 0.03 μM, respectively (Sharma et al., 2019).