Objective: The overall prognosis of ovarian carcinoma is poor. However, the outcome of apparently similar cases is highly variable, and molecular markers that would predict disease outcome in a clinically useful manner are lacking. We investigated the value of p53 expression as a disease determinant in serous carcinoma, which is the most common type of ovarian carcinoma and has shown the highest frequency of p53 alterations.
Methods: Tissue microarray constructed of 522 serous ovarian carcinomas was examined immunohistochemically using DO-7 monoclonal antibody against p53 protein. The findings were correlated with overall and disease-free survival, response to therapy, and clinicopathological characteristics of the patients.
Results: Both excessive and completely negative p53 staining confered poor patient outcome and were considered aberrant p53 expression. Patients with aberrant p53 (59% of the carcinomas) showed 5-year overall survival of 26% (20-31%), whereas patients with normal p53 expression (41% of the carcinomas) showed 5-year overall survival of 79% (95% CI, 74-85%) (P < 0.0001). The association of aberrant p53 with poor prognosis was independent of clinicopathological parameters, e.g., stage and grade. In addition, aberrant p53 status was significantly associated with shorter disease-free survival (P < 0.0001) and poor response to therapy (P < 0.0001). In the most common subgroups, stage III and stage I carcinomas, 5-year overall survival rates for patients showing normal p53 vs. aberrant p53 were 72% vs. 19% (P < 0.0001) and 99% vs. 56% (P < 0.0001), respectively.
Conclusion: P53 expression status divides serous ovarian carcinomas into two distinct subtypes: one with a relatively good prognosis and the other with a particularly poor outcome.