SMAD2 and hepatocellular carcinoma: Since TGF-β signaling pathways are continuously activated in HCC and closely related to their proliferation, apoptosis, and metastasis, we investigated the effects of AST-3424 monotherapy and combination therapy with OXA or 5-Fu on the TGF-β signaling pathway by using its activated form, p-Smad2/3 (tyrosine phosphorylated Smad 2/3).