First, to confirm the effects mediated by tumor cells on fibroblasts are related to Nodal rather than TGF-β in our experiments, the expression of Nodal and TGF-β in B16, B16-Nodal, B16-shNodal, CT26, CT26-Nodal, and CT26-shNodal were checked by western blot. This evidence concerns the gene TGFB1 and neoplasm.