TGFB1 and esophageal squamous cell carcinoma: Consistently, the results obtained from the western blot analysis demonstrated that pretreatment with SB-431542 or si-smad2, specifically targeting NSG1-overexpressing ESCC cells, instigated the downregulation of both the TGF-β/Smad signaling pathway and EMT-associated proteins (Fig. 3G).