In the present study, Smad1/5/8 and Erk1/2 phosphorylation was enhanced by Dragon expression both in cultured colon cancer cells and in xenografts. Inhibition of the Smad1/5/8 and Erk1/2 pathways attenuated Dragon-induced colon cancer cell proliferation. This evidence concerns the gene RGMB and malignant colon neoplasm.