In order to further determine whether Wnt/β-catenin pathway participated in mediating the impact of PlGF on lung cancer cells, we overexpressed PlGF in PC9 cells by transfection with oePlGF plasmid, which were then knocked down β-catenin (Fig. 5a, b) or incubated with XAV939 (10 μmol/L), inhibitor of Wnt/β-catenin pathway, for 24 h. The gene discussed is PGF; the disease is lung cancer.