Prognostic value of the expression of Smad6 and Smad7, as inhibitory smads of the TGF-β superfamily, in esophageal squamous cell carcinoma

Background: The transforming growth factor (TGF-beta) superfamily regulates cell growth in various cells. Previous studies have shown that altered expression of TGF- beta receptors, Smad2 and Smad4, as mediators of TGF- 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 farther effects of TGF-beta superfamily signaling. Materials and Methods: Immunohistochemical staining with anti-Snzad6 and anti-Sinad7 polyclonal antibodies was performed on surgical specimens obtained from 115 patients with esophageal SCC. Results: The expression of Smad6 and Smad7 was inversely con-elated with depth of invasion in the early stages (p = 0. 0003 and p = 0. 0 7 73, 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.