Further, FGL1 knockdown inhibited EGFR and EGFR phosphorylation (p-EGFR1173 and p-EGFR1086), and decreased PARP1 and caspase 3 levels, regardless of the presence of gefitinib (P < 0.05), which implied that FGL1 promotes apoptosis of NSCLC cells PC9 through affecting the expression of PARP1/caspase 3 via lowering the expression and phosphorylation of EGFR. Here, FGL1 is linked to non-small cell lung carcinoma.