Expression Of Phosphorylated AKt And Nuclear Factor-kappaB P65 In Epithelial Ovarian Tumors And Those Possible Implications

Background and ObjectiveOvarian malignant tumor is the third disease that threatens the women health except cervical cancer and carcinoma of endometrium, which can not be diagnosed in early stage but easily metastasize to result in a poor outcome. Many problems haven't be resolved in the research about the pathogenesis of ovarian cancer. Lately abnormal sign transduction pathway has been a focus in resarch of malignant tumors.Many research report PI3K/AKT cascade sign pathway play a crucial role in a wide range of important processes associated with malignant tumor including carcinogenesis, progression, apoptosis, angiogenesis, metastasis and chemoresistance. Due to some pathologic factors, constitutively activated AKT activates it's correlative cascade molecules to induce carcinogenesis and malignant behavior through the regulation of cell cycle , induction of proliferation and inhibition of apoptosis. The cascade molecules regulated by AKT pathway include cyclin-related genes product and anti-apoptosis genes product, et al. nuclear factor-κB(NF-κB) is one of the important cascade molecules regulated by AKT pathway. NF-κB is a type of protein-family made up of complicated polypeptide subunits, whose family members usually exist in the form of homodimer or heterodimer with IκB a , the inhibiter of NF-κB, lies in the cytoplasm. When working together with some active factor , IκB a phosphated by IkappaB kinase (IκK) was degraded, then NF-κB separated from the dimer , transferd to nuclear and restored activity. Activated AKT stimulate the function of NF-κB in the process of conduction of signals through activating IκK. Activated NF-κB can promote proliferation of tumor cells and the formation of vessels in tumor, suppress the apoptosis, and regulate ICAM-1 and MMP-9 to degrade the ECM, which is benifical for the invasion and metastasis of tumor cell.The expression of activated AKT and its correlative cascade molecules in ovarian cancer and possible implacation has seldom been studied. In this research , to determine the expression of p-AKT and NF-κBp65 in ovarian tumor by SP Immunohistochemistry, study their correlation with clinicopathologic parameters and prognosis, analyse the relativity of the two protein help us illuminate the function of p-AKT and NF-κBp65 in the carcinogenesis and progression of ovarian carcinoma, which might provide a new therapeutic target.Material and Methods115 ovarian tissues keeping in the archives in the Department of Pathology, the First Affiliated Hospital of Zhengzhou University from March 2001 to November 2005 were included in the study, which consisted of 68 cases of epithelial ovarian carcinoma, 12 cases of epithelial borderline tumor, 24 cases of epithelial benign tumor and 11 cases of normal ovarian tissue(comparison group). All tissues were paraffin-embedded and cut into sequence slices of 4цm thick. None of the patients had received any therapy before the ovarian cancer tissue was taken. The patients age range from 17 to 73, the mean age is 50±10. 97,there is'not obvious difference among these groups (P<0.05). The epithelial ovarian cancer groups included 44 cases of serous cystadenocarcinoma, 15 cases of mucinous cystadenocarcinoma and 9 cases of endometrioid carcinoma(age≥50:35 cases,age<50: 33 cases;stage I～II :34 cases, stage III～IV:34 cases; and grade G₁ + G₂: 45 cases; grade G₃:23 cases;18 cases with pelvic lymph nodes metastases,50 cases without pelvic lymph nodes metastases; 47 cases with ascites, 21 cases without ascites). The clinical stage of ovarian cancers was determined according to the International Federation of Obstetrics and Gynecology (FIGO) classification. 63 cases with entire data were followed-up from 7～60 months until July 2006. Immunohistochemistry were taken to detect the expression of p-AKT and NF-κBp65 in all above tissues, investigate the association between the positive rate of those with clinical-pathological characters of epithelial ovarian carcinomas and the survival rate of ovarian cancer patients, analyse the relativity of the two protein. Statistical analysis was performed by software SPSS13.0 package. All the test data was separately treated with Chi-square test, correlation analyze, Kaplan Meire survival curve and Cox regression analysis. All of the P values resulted from two-sided statistical test. Statistically significant level was considered as "alpha equals 0.05" (α=0.05).Results1. The positive rate of p-AKT expression in ovarian cancer ,borderline epithelial tumors,benign epithelial tumors and normal ovarian tissues, was 52.9%, 16.7%,12.5% and 9.1% respectively; The positive rate of NF-κBp65 expression of those was 75.0 %, 41.7%,20.8% and 27.2%. The normal ovarian tissues, as the comparison group, was compared with other groups. The positive rate of p-AKT and NF-κBp65 expression in EOC was higher than that in normal ovarian tissues and no statistical significance was found among benign, borderline epithelial tumors and normal ovarian tissues.2. The positive rate of p-AKT expression in grade G₁/G₂ and grade G3 of EOC was 42.2% and 73.9%, statistical significance was found between the two groups(x²=6.136, P=0.013) .The positive rate of p-AKT expression in stage I / II and stage III/IV of EOC was 35.3% and 70.6%, statistical significance was found between the two groups (x²=8.500, P=0.004 ). The positive expression of p-AKT was higher in ovarian cancer with lymph node metastasis than those without (x²=6.061, P=0.014 ), while be independent of factors such as age , tissue types and ascites formation. The positive rate of NF-κBp65 expression in grade G₁/G₂ and grade G₃ of EOC was 64.4% and 95.7%, statistical significance was found between the two groups (x²=7.906, P=0.005) . The positive rate of NF-κBp65 expression in stage I / II and stage III/IV of EOC was 58.8% and 91.2%, statistical significance was found between the two groups (x²=9.490, P=0.002 ) . The positive expression of NF-κBp65 was independent of factors such as age,tissue types,lymph node metastasis and ascites.3. Correlative analysis showed the expression of p-AKT was correlated with the expression of NF-κBp65 in EOC group( r_s=0.272 ,P =0.025) .4. Among the 63 cases followed up, 16 cases survive five years , the accumulative survival rate was 14.57% and the median survival time was 26 months. The 5 cases from 34 cases of positive expression of p-AKT survive five years, the accumulative survival rate was 14.71% and the median survival time was 20 months. The 13 cases from 29 cases of negative expression of p-AKT survive five years, the accumulative survival rate was 37.93% and the median survival time was 31 months. Statistical significance was found between the two groups using Log-Rank test(F =0.009). The10 cases from 50 cases of positive expression of NF-κBp65 survive five years, the accumulative survival rate was 20.00% and the median survival time was 23 months. The 6 cases from 13 cases of negative expression of NF-κBp65 survive five years, the accumulative survival rate was 46.15% and the median survival time was 39 months. Statistical significance was found between the two groups using Log- Rank test(P =0.041).Univariate regression models and multivariate regression models were used to analyse the possible factors influence prognosis including age , tissue types, clinical stages , histological differentiation ,lymph node metastasis and ascites. The result was no factors but clinical stages to be an independent adverse prognostic factor.Conclusions1. p-AKT and NF-κBp65 protein showed high expression in EOC, while showed low expression in normal tissues. There was a close relationship between the positive rate of p-AKT and NF-κBp65 with clinical stages and histological differentiation. Otherwise, the positive expression of p-AKT was higher in ovarian cancer with lymph node metastasis than those without. It proved that p-AKT and NF-κBp65 might play an important role in carcinogenesis, development and metastasis of EOC. 2. The expression of p-AKT protein is correlated with that of NF-κBp65 protein in EOC, implying that p-AKT may cooperate with NF-κBp65 in EOC development. It might provide a new management to therapy EOC in the future.3. The overexpression of p-AKT or NF-κBp65 was negatively related with survival rate of ovarian cancer patients.