p53 is a persistent and predictive marker in advanced ovarian carcinomas: multivariate analysis including comparison with Ki67 immunoreactivity

Abstract

p53 mutation and p53 protein overexpression are common findings in ovarian carcinomas. In order to evaluate the prognostic significance of the p53 status and its role in metastasis, we examined 104 ovarian carcinomas, among them 83 cases with follow-up data, and 40 pairs of primary tumors and metastases, by p53 immunohistochemistry and temperature-gradient gel electrophoresis. Comparison of primary tumors and their metastases revealed identical results in 88%-90% of the cases, indicating that, in most cases, mutant p53 occurs prior to metastatic spread and remains clonally conserved. With respect to all tumors, moderate/high p53 expression was significantly more prevalent in serous-papillary types, carcinomas with high grade, and high Ki67 scores, but was not associated with age, stage, or hormone receptor status. Kaplan-Meier analysis of 83 cases, followed-up for 9-96 months, demonstrated that moderate/high p53 overexpression in the group of 66 stage T3/M1 tumors was associated significantly (P = 0.0028 and P = 0.0105) with shorter overall and recurrence-free survival. Multivariate analysis revealed that advanced clinical stage and p53 positivity were the only independent predictive variables. No significance was seen in regard to second-look results and outcome of 50 patients receiving platinum-based chemotherapy. These observations show that p52 immunohistochemistry is an independent prognostic indicator at the given cut-off level, but does not reliably predict chemotherapy response.