SMAD2 and colorectal neoplasm: TGIF1 is a negative regulator of the transforming growth factor β (TGF-β) signalling pathway, acting as a co-repressor in Smad2/3 complexes.37 Although there is a complex relationship between TGF-β activity and carcinogenesis, TGF-β component inactivation is common in colorectal tumours, and increased TGIF1 may therefore contribute to intestinal tumorigenesis in our mice.