Expression of Proliferating Cell Nuclear Antigen and p53 Protein in Ovarian Epithelial Tumors

ABSTRACT

p53 gene mutation is commonly accepted to be associated with loss of negative cell cycle control and progression of tumors. The proliferative activity of tumor cells is considered to be a valuable indicator of tumor aggressiveness. This study is intended to compare p53 protein expression with cell proliferation rates in the ovarian epithelial tumors according to the various clinicopathological parameters. Immunohistochemistry using monoclonal p53 antibody (DO-1) and PCNA antibody (PC10) was applied to 56 cases of ovarian epithelial tumors including 17 cases of borderline tumor. The results were as follows. Both immunohistochemical staining of PCNA and p53 protein showed positive reactions confined to the nuclei of tumor cells. There were significant differences of p53 protein expression rates between borderline malignancies (11.8%) and cystadenocarcinomas (56.4%) of ovary. The expression rate of p53 protein was not significantly different according to the differentiation and the stage, but the cases of strong positive reaction to p53 protein were more frequently noted in the poorly differentiated and advanced staged tumors. The PCNA indices of p53 strong positive cases were higher than those of p53 weak positive cases. In summary, p53 protein and PCNA expression may be used as an adjuvant in differentiating borderline lesions from carcinomas of ovary and predicting their biological behaviors.