To investigate whether FGL1 plays a role in the acquired resistance of NSCLC cells to EGFR-TKIs, we treated A549, H1975, PC9, and PC9/GR cells with gefitinib at various concentrations (0, 0.625 1.25, 2.5, 5, 10, 20, and 40 μmol/L). Here, EGFR is linked to non-small cell lung carcinoma.