Expression of p53 protein and Ki-67 reactivity in ovarian neoplasms. Correlation with histopathology

The expression of Ki-67 proliferation antigen and its relation to p53 protein was assessed immunohistochemically in malignant and benign ovarian neoplasms, considering the stage of disease and histology of tumors. The comparison of p53 and Ki-67 in tissue sections and respective cyst and/or ascitic fluid cells was also performed. Significant heterogeneity of staining was observed. However, the relationship between p53 and Ki-67 activity in tissue sections and loose cells in individual patients was evident. Moreover, the presence of Ki-67 antigen was closely correlated with p53 protein. It was observed the trend for serous carcinoma to have a higher Ki-67 and p53 positivity versus endometrioid and mucinous carcinomas. However, it was not statistically significant. Both growth fraction as measured by Ki-67 staining and p53 content were significantly higher in stages III and IV compared to stages I and II of ovarian carcinomas (P<.05, and P<.01, respectively). In benign ovarian neoplasms, no p53 reactivity was observed and Ki-67 staining was very low. Our results showed that p53 is not a feature of benign epithelial ovarian tumors and indicate that increased proliferative activity of cells seems to involve immunohistochemically detectable alterations in p53 gene contributing to the evolution of ovarian carcinoma.