To inhibit the tumor progression caused by dysregulation of CDK13-circCDK13-miR-212/miR-449a-E2F5 pathway, we screened some pharmacological inhibitors for different signaling pathways, including p38 MAPK inhibitor, Smad3 inhibitor, ERK1/2 inhibitor, Wnt/β-catenin inhibitor, GSK-3β inhibitor and PI3K inhibitor, to identify potential CDK13 and E2F5 inhibitors. The gene discussed is SMAD3; the disease is neoplasm.