The immunohistochemical expression of p53 and Ki67 in ovarian epithelial borderline tumors. Correlation with clinicopathological factors.

Background: Borderline tumor of the ovary is an epithelial tumor with a low rate of growth and a low malignant potential to invade or metastasize. This tumor often is associated with a significantly better prognosis than epithelial ovarian cancer. Most of these tumors are either serous or mucinous in histology.

Aim: Assessment of p53 and Ki67 immunohistochemical expression in 52 epithelial ovarian tumors, correlation with clinicopathological factors, and comparison between results in benign, borderline, and malignant tumors.

Materials And Methods: From the total number of 125 patients diagnosed with epithelial ovarian neoplasms in the period 2002-2010, 52 operated patients were selected, with serous and mucinous tumors. There were 26 (50%) malignant cases, 15 (28.8%) borderline and 11 (21.15%) benign. We used the monoclonal antibody DO7 and Ki67-MM1.

Results: P53 immunoreactions were positive in 41.66% of malignant serous tumors, most of them (90%) high-grade carcinomas; 6.66% of borderline and none benign tumors were positive. Ki67 was positive in 61.53% of malignant cases, with higher percents in advanced clinical stages. Ki67 immunoreactions were also positive in borderline and benign tumors, with lower percents, 13.3% respectively 9.09%.

Conclusions: We found almost similar frequency of immunostaining in borderline tumors and low-grade invasive serous carcinomas in contrast to the significantly higher frequency of p53 mutations in high-grade serous carcinomas. Proliferative activity as assessed by Ki67 staining does not explain any possible relationship of serous borderline tumors to epithelial ovarian cancer.