PTEN and p53 expression in primary ovarian carcinomas: immunohistochemical study and discussion of pathogenetic mechanisms.

Proapoptotic molecules have been studied in epithelial ovarian neoplasms as possible indicators of the pathogenetic pathways, as targets for new therapeutic approaches, and as prognostic markers. PTEN and p53 are proteins that have many different regulatory functions, including apoptosis. We have studied their immunohistochemical expression in 70 cases of primary ovarian carcinomas (26 serous, 27 endometrioid, and 17 mucinous) and compared the results with morphologic parameters (histologic grade, subtype) and clinical data (age, stage, tumor size). Statistical analyses showed a significantly higher expression of p53 in histologically high-grade tumors (grades 2 and 3), mainly of the serous subtype. A statistical tendency of higher expression of p53 in older patients (P= 0.08) was also observed. The loss of expression of PTEN was significantly more frequent in grade 1 endometrioid adenocarcinomas. These markers did not show association with volume or stage of the tumor. p53 is associated with serous carcinoma, loss of differentiation, and older patients, whereas PTEN inactivation is an early event in carcinogenesis of the endometrioid subtype, as observed in type I endometrial carcinoma. Our results are in keeping with different pathogenetic pathways in subtypes of ovarian carcinoma, prompting the search for new strategies of prevention and treatment.