SMAD7 and neoplasm: Increase in the metastatic potential of this cell line by Smad7 may involve (1) blockade of TGF-β-mediated tumour suppressor function by Smad7, (2) cooperation between mutated K-Ras (in FET cells) and activated Smad2 generated as a result of metastasis to the liver and (3) cooperation between activated K-Ras and higher levels of Smad7.