p53 protein detected by immunohistochemistry as a prognostic factor in patients with epithelial ovarian carcinoma

The clinical significance of p53 suppressor gene nucleoprotein immunostaining in ovarian epithelial cancer has not been determined.

p53 protein expression was studied by immunohistochemistry from paraffin embedded tissue in a series of 136 patients with malignant ovarian epithelial tumors. The median follow-up time of the patients still alive was 10 years.

Sixty (44%) carcinomas stained clearly positive for p53 protein. Positive staining for p53 protein was associated with the serous histologic type (P = 0.0006), a higher than the median S-phase fraction size determined by DNA flow cytometry (P = 0.02), and poor histologic grade of differentiation (P = 0.04), but not with the International Federation of Gynecology and Obstetrics (FIGO) stage, age at diagnosis, or DNA ploidy. Cancers with positive staining had only 17% 5-year and 9% 15-year survival rates compared with 42% 5-year and 36% 15-year survival rates corrected for intercurrent deaths among the rest of patients (P = 0.002). In a multivariate analysis, positive p53 staining was associated with poor survival (relative risk of death, 1.8, 95% confidence interval [CI], 1.2-2.9) together with less than radical surgery (nonradical vs. radical: RR, 5.5; 95% CI, 2.2-13.6), and advanced FIGO stage (RR, 1.4; 95% CI, 1.0-2.0).

Although p53 protein immunostaining is associated with several other prognostic factors in epithelial ovarian cancer, it may also have independent prognostic value in this disease.