Afatinib, ceritinib, gefitinib and osimertinib were purchased from Selleck Chemicals. Carboplatin, cisplatin, docetaxel and paclitaxel were purchased from Sigma-Aldrich; Merck KGaA. Pemetrexed was purchased from Toronto Research Chemicals (37 (link),38 (link)). A549 and A549/KL-1 cells (2,000 cells/well) were seeded into 96-well plates, and the drugs were added in increasing concentrations (0, 0.01, 0.1, 1, 10 and 100 µM) at room temperature. The half maximal inhibitory concentration (IC50) value was defined as the concentration of an anticancer agent required to reduce growth by 50%. The corrected absorbance of each sample compared with that of the untreated control was calculated by MTT assay using the absorbance wavelength at 570 nm.