EGFR and neoplasm: We evaluated the anti-tumor properties of afatinib and osimertinib in four EGFR-mutant lung adenocarcinoma cell lines (i.e., PC-9, HCC827, H1975, and H1650) by the 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium, inner salt (MTS) assay.