Study On The Expression Of E-cad And Its Associated Protein In Epithelial Ovarian Carcinoma And Clinical Significance

Aim: To study the expression of the epithelial adhesion molecule E-cadherin and its associated proteins α- catenin and β- catenin in normal ovaries, benign ovarian tumours and epithelial ovarian carcinomas, as well as correlations with clinicopathological characteristics.Method: The protein levels of E - cad, α- cat and β- cat were detected by an immunohistochemical analysis in formalin-fixed, paraffin-embedded samples of 32 normal ovaries, 38 benign epithelial ovarian tumours and 106 epithelial ovarian carcinomas, using the monoclonal antibodies specific against these three proteins respectively; mRNA level was analyzed by RT-PCR in the fresh specimens of 31 epithelial ovarian carcinomas with Gel-pro Analyzer.Result:1. E - cad expression was absent in normal ovarian surface epithelium; in benign epithelial ovarian tumours, E - cad was strongly expressed, this staining was located on the tumour cell membrane; in epithelial ovarian carcinomas, E - cad expression was different from each other, apart from membrane staining, cytoplasmical staining was accompanied in a few cases. Compared with staining of benign tumors, E - cad expression in epithelial ovarian carcinomas was apparently decreased, which was statistically significant(P<0.05).2. Expression of a - cat and (3 - cat was consistently detected on the membrane of normal ovarian surface epithelium cells and benign epithelial ovarian tumour cells; while their expression was reduced or lost in epithelial ovarian carcinomas. The difference between benign and malignant tumors was significant(ta=2.340, .PO.05; 10=2.233,3. The expression level of E - cad, a - cat and 3 - cat in poorlydifferentiated carcinomas was significantly reduced compared with serous cystadenocarcinomas and mucinous cystadenocarcinomas (FE=4.886, P<0.05). For E - cad expression, there was no significant difference in different histological grade of epithelial ovarian carcinomas, and this result is the same to a- cat and 3 - cat expression. As to clinical stage, E - cad expression was significantly higher in I ~ II stage than in III ~ IV stage, and the expression of a - cat and 3 - cat also had the same result.4. The significant correlation was found between the expression of E - cad and the duration of survival. Patients with negative expression of E -cad presented a significantly shorter survival than the remaining patients.5. In a few endometrioid carcinomas, 3 - cat expression was found in cytoplasm and nuclei of cancer cells, which is different from the usual staining pattern.6. The correlations between E - cad and a - cat, E - cad and 3 - cat, a- cat and 3 - cat were significantly related in epithelial ovarian carcinomas.7. The expression of E - cad mRNA was not statistically different in the different histological types of epithelial ovarian carcinomas, which is the same to histological grade and clinical stage of tumors.Conclusion: E - cad was induced in the development of ovarian tumours. Expression of E - cad was correlated with tumour differentiation. E - cad was expressed in highly and moderately differentiated tumours, while in poorly or undifferentiated tumours, E - cad was failed to stain or expressed at a reduced level. E - cad expression was significant correlation with survival time, and its expression had prognostic value in epithelial ovarian cancers. All these three proteins were reduced or failed to stain in some ovarian carcinomas of higherclinical stage, indicating they were associated with tumor malignancy, such as invasion and metastasis.