Effect And Expressions Of Aurora-B, Survivin In Benign And Malignant Epithelial Ovarian Cancinoma

Backgroud and PurposeOvarian cancer is one of the three gynecological malignant tumors, whose mortality rates are much higher than the other. The reasons lead to the result are these: Firstly, ovaries lie deeply in the pelvic, and most of the patients suffering the disease don not have specific generalized symptoms in early stage. Second, we don not have sensitive and specific diagnosis, and we have not maken out the pathogenesis of the disease. In fact, it is not till advanced stage that most patients are found, and only 25%-30% of them have 5-year survival. Now, many academicians are investigating the pathogenesis of the ovary cancer. As a member of newly emerged aurora-kinase, Aurora-B is also a kind of serine/threonine kinase, and plays a key role in the process of cell division. Some studies have indicated that the overexpression of Aurora-B was associated with the occurence and development of many kinds of cancer. Survivin is a member of the inhibitors of the apoptosis protein family, and it is known to be overexpressed in various carcinoma tissues. Besides suppressing the apoptosis, Survivin also takes part in the cell cycle regulation, division, multiplication and the formation of the blood vessel. Spindle assembly and positioning, the proper chromosome replication and segregation, exact cytokinesis and so on are all dependent on the precise regulation of Aurora-B and Survivin. Now, the study about the relationship between the two factors and ovarian cancer is still rare. In our experiment, we observed the expression and distribution of Aurora-B and Survivin in the epithelial ovarian cancer (EOC), so as to explore the function of Aurora-B and Survivin in the occurrence and development of epithelial ovarian cancer.Materials and Methods1 Experimental samples:We observed 96 ovarian tissue with histopathology diagnosis in the First Affiliated Hospital of Zhengzhou University during June 2009 to May 2010, and divided them into there groups by pathology. The first group had 18 normal ovary tissue(short for Normal group), and mean age was 53.25±6.1 years old(range,40- 78), the second group had 36 benign ovarian epithelial tumor(short for Benign group), and mean age was 47.30±7.2 years old(range,19-63), of which 20 cases were diagnosed as serous cystadenoma,16 cases as mucinous cystadenoma, the third group included 42 malignant epithelial ovarian cancer(short for Malignant group), mean age (58.69±5.7)years old, (range,22-86), of which 32 cases were diagnosed as serous carcinoma,10 cases as mucinous carcinoma. According to FIGO(2000) stage, of the malignant tumor, there were 10 cases of the stagesⅠⅡperiod,32 cases of the stagesⅢ～Ⅳperiod. According to WHO(1973) histolological grade, there were 9 cases were well differentiated carcinomas,33 cases were moderate and poorly differentiated carcinomas, and 27 cases with lymph node metastasis,28 cases with ascites. Three groups had no significant difference in age and had no history of cancers, and never suffered radiotherapy and chemotherapy before surgery. These samples were divided into two parts, one was put in liquid nitrogen, avoided freezing and melting time after time. The other was fixed in 10% phosphate-buffered formalin embedded in paraffin, and made serial 4μm thick sections.2 Test methods:We detected the expression levels of Aurora-B and Survivin protein in the Normal, Benign and Malignant group using technique of immunohistochemical. We investigate Aurora-B and Survivin mRNA expressions with reverse transcription-polymerase (RT-PCR). Then we compared the difference among groups in order to investigate the relationship between the two factors and the clinicopathological feature of ovarian cancer.3 Statistical analysis:The SPSS statistical package program 16.0 was used: qualitative analysis usingχ2 test or Fisher's exact probabilities; quantitative analysis with t-test, one-way analysis of variance or kruskal-Wallis rank sum test; multiple comparison with Bonferroni method; the distributional correlation between Aurora-B protein and Survivin protein, Aurora-B mRNA and Survivin mRNA were obtained using the Spearman's rank correlation and Pearson's product-moment correlation coefficient respectively.α=0.05 were deemed significant, while using multiple comparison, the significance level should be corrected, andα'=α/n (n is the number of comparisons among groups.Results1 Aurora-B protein mainly expressed in the nuclear of EOC cell, and in the cytoplasm by chance. The positive rate of Aurora-B protein in EOC tissue was 52.38% (22/42), in benign ovarian tumor tissue was 13.89%(5/36), and in normal ovary tissue was 5.56%(1/18). The differences among the three groups were significant(χ2=19.880, P=0.000). The expression level of Aurora-B protein in Malignant group was significantly higher than that in Benign group(χ2=12.690, P=0.000) and Normal group(χ2=11.687, P=0.001), while, there was not statistical difference about the positive rate between Benign group and Normal group(P=0.651>0.017).2 In EOC tissue, the positive rate of Aurora-B protein inⅢ/Ⅳstage group (62.50%,20/32) was higher than that inⅠ/Ⅱstage group(20.00%,2/10). The difference was significant (χ2=3.945, P=0.047). The same to lymph node metastasis group (66.67%,18/27) and without lymph node metastasis group(26.67%,4/15), (χ2= 6.185, P=0.013); ascites group(64.29%,18/28) and without ascites group (28.57%,4/14), (χ2=4.773, P=0.029). While, Aurora-B protein expression in tumors with well differentiation(33.33%,3/9) was not significantly lower than that with moderate and poor differentiation(57.58%,19/33),P>0.05.3 Survivin protein strongly expressed in the cytoplasm of EOC cell, and sometimes in the nuclear. The positive rates of Survivin in EOC tissue(85.71%, 36/42), benign ovary tumor tissue(38.89%,14/36), and normal ovary tissue (11.11%,2/18) were significantly different(χ2= 33.662, P=0.000). The expression of Survivn protein in Malignant group was significantly higher than that in Benign group(χ2=18.471, P=0.000) and Normal group(χ2= 30.198, P=0.000), while, there was not statistical difference about the positive rate between Benign group and Normal group(P=0.035>0.017).4 In EOC tissue, the positive rate of Survivn protein inⅢ/Ⅳstage group (93.75%,30/32) was higher than that inⅠ/Ⅱstage group(60.00%,6/10). The difference was significant(P=0.021). The same to ascites group(96.43%,27/28) and without ascites group(64.29%,9/14),(P=0.011). While, Survivin protein positive rates in lymph node metastasis group(92.59%,25/27) and without lymph node metastasis group (73.33%,11/15), in well-differentiated tumors (77.78%,7/9) and poorly differentiated tumors (87.88%,29/33) were not significantly different (P>0.05).5 As far as to the mRNA of Aurora-B and Survivin, they all had their own specific band (Aurora-B 1035bp, Survivn 201bp). The expression differences about Aurora-B mRNA and Survivn mRNA among the Normal group(Aurora-B: 0.031±0.006, Survivin:0.113±0.014), the Benign group (0.395±0.046,0.584±0.048) and the malignant group(0.735±0.065,0.978±0.103) were significant(P all<0.05). Both Aurora-B and Survivn, the differences of their mRNA levels betweenⅢ/Ⅳstage group andⅠ/Ⅱstage group were evidently (Aurora-B 0.734±0.035 vs 0.719±0.040; Survivin 0.976±0.098 vs 0.965±0.125), and the differences were significant(P<0.05); the same to lymph node metastasis and without lymph node metastasis group (Aurora-B 0.723+0.039 vs 0.714±0.024; Survivin 0.981±0.099 vs 0.967±0.092), ascites group and without ascites group (Aurora-B 0.731±0.017 vs 0.727±0.040; Survivin 0.983±0.089 vs 0.968±0.092), P all <0.05. While, the mRNA expressions of both factors in tumors with well differentiation were not significantly different from that with moderate and poor differentiation(Aurora-B 0.728±0.032 vs 0.736±0.052; Survivin 0.959±0.031 vs 0.964±0.025), P>0.05.6 In the malignant ovarian carcinoma tissue, the Spearman correlation coefficient between Aurora-B protein and Survivin protein was 0.339, P=0.001, the Pearson correlation coefficient between Aurora-B mRNA and Survivin mRNA was 0.740, P=0.000. And these indicated the two factors had positive correlation.Conclusion1 The expressions of Aurora B and Survivin protein in malignant epithelial ovarian tumors were significantly higher, especially those with advaced stage, lymph node metastasis and ascites, we speculated that maybe both the factors were associated with the incidence, development, infiltration and metastasis of ovarian career.2 Aurora-B and Survivin had a syntropic correlation with each other, and maybe they had synergistic effect in the occurrence and development of ovarian cancer.