The Expression And Significance Of P53 And BRCA1 In Endometrial Carcinoma

ObjectiveEndometrial carcinoma is one of the three most common female reproductive system malignant tumors, whose incidence goes up every year all over the world, and it is classified into two types according to the cause, one is estrogen-dependent endometrial carcinoma(TypeI),the other one is non-estrogen-dependent endometrial carcinoma(TypeII), their change in molecular biological level are different.p53 gene is the most associated anti-oncogene in human malignant tumors, whose mutation leads to onset of carcinoma.BRCA1 gene is breast carcinoma-ovarian cancer predisposing gene, whose mutation increases risk of onset of breast carcinoma and ovarian cancer. In this study, we use immunohistochemical technique to detect the expression of p53 and BRCA1 in normal endometrium, endometrial atypical hyperplasia and TypeI endometrial carcinoma and typeII endometrial carcinoma, and try to elucidate the correlation between the expression level of p53,BRCA1 and the relative clinicopathologc features.Meterials and Methods1 .Case selectionA total of 60 paraffin-embedded tissue sections of endometrial carcinoma were retrieved from the surgical Pathology department at Chinese Medical University Shengjing Hospital from 2003 to 2007. The selected clinical cases were Confirmed by pathological diagnosis. All of the patients were preoperatively untreated, without other tumors. Meanwhile, another 15 cases with endometrial atypical hyperplasia and 13 case with normal endometrium were selected as control.2.Primary reagents and instrumentsmurine monoclonal antibodies against p53, the murine polyclonal antibodyes against BRCA1,as well as the immunohistochemistry S-P kits and the Goat antirabbit IgG marked by Biotin, and those routine reagents and instruments used in immunohistochemistry.3.MethodsTissue samples embedded in paraffin were cut into 5μm-thick sections. These sections were deparaffinized with xylene, and rehydrated with a series of graded alcohols. The slides were immersed in methanol containing 3% H₂O₂ to block endogenous Peroxidase activeity. After heat antigen retrieve processing, the sections were treated with normal serum to block nonspecific staining. Sections were then incubated with anti-p53 and anti-BRCA1 primary antibodies respectively at 4℃overnght in a moisture chamber. This was followed by incubation with a biotinylated secondary antibody at room temperature for 30 minutes and thereafter incubation with horseradish peroxidase conjugated avidinbiotin complex at room temperature for 30 minutes. Immunostaining was visualized using, 3V-diaminobenzidine tetrahydrochloide substrate. Slides were counterstained with hematoxylin. Then the sections were dehydrated and cleared and mounted with resin. Tissue ample of breast cancer with Known antigen of p53 and BRCA1 were used as positive control of p53 and BRCA1 immunoassaying respcctively, PBS replacing the primary antibodies was used as negatives controls.4.Results JudgmentThe intranuclear brown granule was considered as p53 Immunostaining and interspongioplastic substance or intranuclear stain is considered as BRCA1 positive. The stained results of p53 and BRCA1 were measured by the Product of the precent of Positive stain and the Percentage of Positive cells numbers in all congeneric cells.5.Statistical Analysis All the data was processed by chi-square test or Fisher exact probability test using SPSS11.5 software Package.Results1.the expression of p53Statistical analysis revealed that the expression of p53 protein is negatively associated with differential extent of tumor cells. The positive expression rate in research team is higher than that in control team. The expression level of p53 is greater in type II endometrial carcinoma than type I endometrial carcinoma. but have no significance statistically. There was no relationship between the p53 expression and the clinical stage, histopathological classification, invasion of myometrium and lymphoid metastasis status(P>0.05). The expression of p53 was associated with histologcal grade in endometrial carcinomas. (x²=6.896, P<0.05)2.the expression of BRCA1There was no relationship between the BRCA1 expression and the tumor differentiation, clinical stage, invasion of myometrium and lymphoid metastasis status (P>0.05).Positive expression rate of BRCA in UPSC was much more lower than that in normal endometrium.(P=0.015)3.the expression of p53 and BRCA1 Statistical analysis revealed there are no significance correlation between the Expression of the two genes.Conclusion1.p53 gene participates in the onset of endometrial carcinoma, the expression of p53 gene increases as tumor cell differential extent decreases, can be used as index to evaluate the malignant extent of endometrial carcinoma.2.In this study, there is significant differentiation between the expression of BRCA1 in UPSC and in normal endomembrane, which reveals that BRCA1 expression may be involved in the onset of UPSC.3. It's not sure that there is cooperation between the expression of p53 gene and BRCA1 gene in endometrial carcinoma.