Alpha-folate Receptor Expression in Epithelial Ovarian Carcinoma and Non-neoplastic Ovarian Tissue

Background: The goal of this study was to evaluate the expression pattern and intracellular localization of alpha-folate receptor (α-FR) protein in human ovarian carcinoma compared with non-neoplastic ovarian tissue. Materials and Methods: Using immunohistochemistry (IHC), α-FR protein expression was analyzed in specimens of 104 human ovarian carcinomas and 30 non-neoplastic ovaries. Results: In 97% of the ovarian carcinomas, clear α-FR protein expression was detected (14% weak, 39% moderate, 44% strong). In the non-neoplastic ovaries, no (37% ) or only weak (63% ) expression was observed (p<0.0001). The tumor cells were characterized by a diffuse and hom ogen eous staining pattern. In tumor and non-tumor tissue, α-FR protein was detected predominantly in the cellular cytoplasm. In 41% of the ovarian carcinomas, cytoplasmic expression was localized towards the outer boarders of the invasive tumor cells and 30% exhibited additional nuclear α-FR protein expression. Conclusion: Compared with non- neoplastic ovaries, α-FR protein is overexpressed in human ovarian carcinoma tissue. Ovarian cancer is the third most common gynecological malignancy and the leading cause of death from gynecological cancer in the industrialized nations (5). Despite advances in the treatment of ovarian cancer, the rather low overall survival rate also reflects a limited efficacy of chemotherapeutic regimens in the case of advanced stage disease (4). In this paradigm, recently described tumorspecific molecular targets such as the alpha-folate receptor (α-FR) may enrich conventional chemotherapeutic strategies and thus improve the outcome of patients with ovarian cancer (14, 21, 26, 32).