TGFB1 and colorectal carcinoma: And snail is a downstream target gene of TGF-β that mediates the tumor-promoting effects of TGF-β (Moon et al., 2017), and this gene is also a key factor in the tumor-promoting effects of fibroblasts in CRC (Herrera et al., 2014), so it is reasonable to hypothesize that Nodal promotes the progression of CRC by mediating the formation of CAFs through the Snail signaling pathway.