Stathmin is a Marker of Progression and Poor Prognosis in Esophageal Carcinoma

Stathmin, also called oncoprotein 18, is a founding member of the family of microtubule-destabilizing proteinsthat play a critical role in the regulation of mitosis. At the same time stathmin has been recognized as one ofresponsible factors in cancer cells. The aim of this study was to assess stathmin status, its correlations withclinicopathological parameters and its role as a progosnostic marker in EC patients. The protein and mRNAlevels of stathmin were examined byimmunohistochemistry (IHC) and in situ hybridization in 100EC tissuesand adjacent noncancerous tissues. mRNA and protein expression of stathmin in three EC cell lines(EC9706,ECa109, EC1 commonly used in research) were also analyzed using immunocytochemistry, western blot andin situ hybridization. The prognostic value of Stathmin expression within the tumor tissues were assessed byCox regression and Kaplan-Meier analysis. We showed that stathmin expression was significantly higher in ECtissues than in adjacent noncancerous tissues. High stathmin immunostaining score in the EC was positivelycorrelated with tumor differentiation, Tumor invasion, Lymph node metastases, and TNM stage. In addition, wedemonstrated that three EC cell lines examined, were constitutively expressing a high level of stathmin. Of those,EC-1 showed the strongest mRNA and protein expression for the stathmin analyzed. Kaplan-Meier analysisshowed that significantly longer 5-year survival rate was seen in EC patients with high Stathmin expression,compared to those with low expression of Stathmin expression. Furthermore, multivariate Cox proportionalhazard analyses revealed that Stathmin was an independent factors affecting the overall survival probability.In conclusion, our data provide a basis for the concept that stathmin might be associated with EC developmentand progression.. High levels of Stathmin expression in the tumor tissues may be a good prognostic marker forpatients with EC.