Prognostic Value of the Expression of Smad6 and Smad7, as Inhibitory Smads of the TGF-β Superfamily, in Esophageal Squamous Cell Carcinoma

Abstract

Background: The transforming growth factor β (TGF-β) superfamily regulates cell growth in various cells. Previous studies have shown that altered expression of TGF-β receptors, Smad2 and Smad4, as mediators of TGF-β superfamily signaling, contributes to tumor progression in esophageal squamous cell carcinoma (SCC). The expression of Smad6 and Smad7 as negative regulators was examined, to investigate the further effects of TGF-β superfamily signaling. Materials and Methods: Immunohistochemical staining with anti-Smad6 and anti-Smad7 polyclonal antibodies was performed on surgical specimens obtained from 115 patients with esophageal SCC. Results: The expression of Smad6 and Smad7 was inversely correlated with depth of invasion in the early stages (p=0.0003 and p=0.0173, respectively). Moreover, there was a significant correlation between the expression of Smad6 and Smad7, and poor survival rate (p=0.0078 and p=0.0207, respectively). Conclusion: Smad6 and Smad7 expression affects the progression of early lesions of esophageal SCC and indicates a poor prognosis.