Caveolin-1 expression in advanced-stage ovarian carcinoma - A clinicopathologic study

Objective. The aim of this study was to analyze the correlation among the e xpression of caveolin-1, the protein constituent of caveolae, and disease o utcome in advanced-stage ovarian carcinomas. Methods. Sections from 76 primary ovarian carcinomas and metastatic lesions from 45 patients diagnosed with advanced-stage ovarian carcinoma (FIGO sta ges III-IV) were evaluated for caveolin-1 expression using immunohistochemi stry. Patients were divided into long-term survivors and short-term survivo rs based on disease outcome. Twenty nonneoplastic fallopian tubes and ovari es were additionally studied. Results. The mean follow-up period was 70 months. The mean values for disea se-free survival and overall survival were 109 and 125 months for long-term survivors, compared to 3 and 21 months for short-term survivors, respectiv ely. Caveolin-1 expression was localized to the cell membrane in 24/76 (32% ) specimens and was detected in the cytoplasm in 52/76 (68%) cases. Both pa tterns were more often detected in metastases, when compared with primary t umors. In addition, membrane immunoreactivity was more often seen in tumor of short-term survivors. These differences did not reach statistical signif icance (P > 0.05), Combined membrane and cytoplasmic immunoreactivity was s een in 17/20 (85%) nonneoplastic lesions. Despite its role in tyrosine-kina se-mediated signal transduction in vitro studies, caveolin-1 expression in carcinomas showed no association with the protein expression of c-erbB-2 an d epidermal growth factor receptor, evaluated in a previous study of this p atient cohort. Conclusions. This study provides the first in vivo evidence of caveolin-1 m embrane expression in human malignancies. Caveolin-1 is often expressed in advanced-stage ovarian carcinoma, but does not appear to be a powerful pred ictor of disease outcome in these tumors. The reduced expression level in c arcinomas compared to nonneoplastic epithelium may point to a role for cave olin-1 as a tumor suppressor gene, (C) 2001 Academic Press.