Abstract

Objective. Approximately 50% of human malignancies present with mutations in p53, which is the most common tumor suppressor gene involved with human malignancies. Bcl- 2 is a protooncogene, and expression of its protein product is associated with a better prognosis in several malignancies. Ki-67 is a marker of cellular proliferation. The purpose of this study was to determine whether simultaneous detection of p53, bcl-2 and Ki-67 using immunohistochemical staining can be used as a diagnostic factor in the assessment of human ovarian epithelial tumors.

Materials and Methods. The study was performed on formalin- fixed, paraffin-embedded tissue samples from 75 epithelial ovarian tumors, 15 serous cystadenomas, 15 mucinous cystadenomas, 5 borderline serous cystadenomas, 5 borderline mucinous cystadenomas, 15 serous cystadenocarcinomas, 15 mucinous cystadenocarcinomas and 5 endometrioid carcinomas. Immunohistochemical staining was performed using monoclonal antibodies against p53, bcl-2, and Ki-67(MIB1).

Results. Anti-p53 reactivity was observed in 14 tumors, all of which were malignant tumors, and no reactivity was observed in borderline or benign tumors. Overexpression of bcl- 2 was observed in 12 benign neoplasms (40%), 5 of which were borderline (50%), but was not observed in any of the malignant tumors. There was a statistically significantly higher level of Ki-67 LI positivity in the malignant tumors than in the benign and borderline tumors (p<0.005).

Conclusion. These data show significant differences in the expression of these markers in ovarian tumors and suggest a possible role for these tumor-associated genes as supplemental tools in diagnostic pathology. Furthermore, our findings support the redesignation of low malignant potential tumors (current nomenclature) to benign ovarian carcinoma.