SMAD2 and Hepatic fibrosis: In support of our data that STAT−/− mice had high activation of the TGF-β signaling pathway during liver fibrosis [27], knockdown of STAT1 enhances TGF-β1-induced phospho-Smad2, whereas overexpression of STAT1 suppresses TGF-β1-induced phospho-Smad2, strongly pointing toward the influence of STAT1 on TGF-β signaling pathway.