| Objective:1. To detect the hypermethylation of E-cadherin gene in the plasma and tissue of ovarian cancer patients, explore the correlation between methylation of E-cadherin promoter and clinicopathologic variables in patients with ovarian carcinoma.2. Detection of malignant, borderline and benign ovarian carcinoma and normal ovarian tissue E-cadherin protein expression, analysis of E-cadherin gene promoter methylation and protein expression.3. Detection of methyl-binding protein MeCP2 expression in ovarian tissues, to explore the relationship the E-cadherin promoter methylation and MeCP2, investigate the correlation with clinical pathological features.Method:1. Detect the E-cadherin gene promoter methylation of plasma and tissue of ovarian cancer patients by nested methylation-specific PCR respectively. Use the single-strand conformation polymorphism analysis combined with DNA sequencing to analyze the results.2. Detected by immunohistochemistry E-cadherin in the groups of ovarian tissue.3. In situ hybridization to detect the expression of methylated binding protein MeCP2.Results:1. Hypermethylation of the E-cadherin presented in 66.0%(31/47) of the plasma samples and 70.2%(33/47) of the tissues in epithelial ovarian cancer, significantly higher than other groups. Plasma E-cadherin gene promoter methylation status are closely related with the tissue (r=0.457,P<0.05), the overall compliance rate of methylation between 78.7%(37/47).2. Epithelial ovarian cancer patients and tissue E-cadherin gene methylation detection rate of well-differentiated tumor grade were significantly higher than in the poorly differentiated group (t=14.805, P<0.05; t=4.215,P<0.05); epithelial ovarian cancer in patients with advanced plasma and tissue E-cad promoter methylation were significantly higher than those detected in the early (t=10.900, P<0.05; t=9.323, P<0.05); peritoneal washing fluid, or ascites cytology-positive, lymph node metastasis the expression of E-cad were higher than negative and non-metastasis group, the differences were statistically significant according to (P<0.05).3. Normal ovarian surface epithelium showed no expression of E-cad; E-cad expression in poorly differentiated ovarian adenocarcinoma was higher than other types of cancer; E-cad expression was negatively correlated with the pathological grade (r=-0.705, P<0.05); the level of E-cad expression in early ovarian cancer was higher than that of advanced ovarian cancer (t=2.456,P<0.05); ascites cells examination negative, lymph node negative E-cad expression was higher than the positive groups, but the differences were no statistically significant (t=0.502, P>0.05;t=0.195, P>0.05).4. MeCP2 expression in all groups, but in malignant group were significantly higher than benign and normal group (t=1.79,P<0.05;t=2.05,P<0.05), but had no statistically significant with the borderline group (t=0.08,P>0.05); MeCP2 in mucinous ovarian adenocarcinoma was significantly higher than other types (F= 2.754,P<0.05); the expression of MeCP2 in poorly differentiated carcinoma is higher than well-differentiated carcinoma(t=5.201,P<0.05); advanced stage group is higher than the early stage group(t=3.438; P<0.05);the expression of MeCP2in ascites cytology positive, lymph node metastasis groups were higher than negative groups, but the difference was not significance (P>0.05).5. E-cad promoter methylation of E-cad expression group was lower than non-methylated group, the difference was statistically significant (t=8.66, P<0.05), E-cad promoter methylation and E-cad expression was negatively correlated (r=-0.386,P<0.05); the MeCP2 protein expression and E-cad expression were negatively correlated (r=-0.312,P<0.05); E-cad promoter methylation and MeCP2 has no correlation.6. With the method of Kaplan-Merier disease free survival (DFS) analysis showed that there are no correlation between the survival and the expression of E-cad status (Long-rank test value of 0.540,P>0.05), but the E-cad promoter unmethylation group and the MeCP2-negative and weak group showed relativity of DFS than methylation group and strong positive group (Long-rank test value of 3.839 and 4.803, P<0.05)Conclusion: 1. E-cad was induced in epithelial ovarian tumor development, the expression of E-cad in malignant and borderline epithelial ovarian cancer is higher than the benign and normal group.It is an important event in the development process of ovarian cancer.2. DNA methylation can occur early in carcinogenesis, its expression product can be changed back. E-cad promoter methylation rate in malignant and borderline epithelial ovarian cancer is higher than the other groups, and it was associated with pathological features.3. The detecetion of E-cad promoter methylation status in plasma has a good relationship with the tissue, and the patient's tumor grade and clinical stage are closely related.It could be a simple, noninvasive, quick biomarkers materials for clinical application.4. MeCP2 in epithelial ovarian cancer was significantly higher than other groups, advanced poorly differentiated epithelial ovarian cancer were significantly higher than well-differentiated early stage, suggesting that MeCP2 expression may be used to detect epithelial ovarian cancer in disease progression and prognosis of biological markers.5. E-cad promoter methylation in epithelial ovarian cancer is correlated with the protein expression, promoter methylation is the main mechanism for gene suppression, but addition there are other mechanisms involved in epigenetic gene changes of a large number of MeCP2 expression and they cause the gene silencing together. |
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