Fig. 1

Sensitivity of A549, H1975, PC9, and PC9/GR cells to gefitinib (x ± s, n = 5). a Inhibition of cell proliferation of A549, H1975, PC9, and PC9/GR cells by gefitinib as measured by CCK-8 assays. b IC50 values of gefitinib in A549, H1975, PC9, and PC9/GR cells, calculated using GraphPad. Students t-test‘was used to compare the means of IC50 values of A549, H1975, PC9, and PC9/GR cells by gefitinib. *P < 0.05 compared with A549; #P < 0.05 compared with H1975; △P < 0.05 compared with PC9