SMAD7 and hepatocellular carcinoma: Given the dual role of TGF-β, displaying either cytostatic or pro-tumorogenic properties, we first characterized our 7 HCC cell lines for TGF-β pathway protein expression (TGFΒR1, TGFΒR2, Smad2, Smad3, Smad4, Smad7) and TGF-β dependent effects on cell proliferation in order to select the most appropriate models to study TGF-β inhibitors.