Role of p53 alteration in primary peritoneal carcinoma.

Although the clinicopathologic features of primary peritoneal carcinoma (PPC) in women are relatively well defined, the molecular pathogenesis of the disease has not been examined. The object of this study was to assess the biological significance of p53 alterations in PPC. Twenty-nine PPCs studied for p53 protein accumulation with monoclonal antibody DO-7 consisted of 26 serous carcinomas, one clear cell carcinoma, one tumor with endometrioid features, and one malignant mixed müllerian tumor. P53 was overexpressed in 83% of all PPCs and in 81% of the serous PPCs. Among eight immunopositive tumors with at least two distinct anatomic sites sampled, six tumors showed concordance, whereas two tumors showed discordance for p53 immunopositivity. The latter two tumors support the concept of a multifocal origin of PPC. This is the first report to suggest that loss of p53 function plays an important role in the development of PPC and might contribute to the poor prognosis of this disease. Parallels to serous papillary carcinomas of the uterus and ovary are discussed.