The effect of chemotherapy on expression of folate receptor-alpha in ovarian cancer

Folate receptor alpha (FR-alpha) has been identified as a potential target in ovarian cancer for diagnostic and therapeutic purposes, based on its overexpression in serous epithelial ovarian carcinoma. The effect of chemotherapy on FR-alpha expression may be important in the applicability of FR-alpha directed agents in the case of residual tumor tissue. The objective of this study was to assess FR-alpha expression in ovarian carcinoma and to evaluate whether FR-alpha expression is altered by chemotherapy.FR-alpha expression was analyzed by semi-quantitative scoring of immunohistochemical staining on tissue microarrays (TMAs) from a database containing 361 ovarian cancer tissue samples, of which 210 serous and 116 non-serous carcinoma (35 missing). Serous carcinoma samples included 28 matched samples with tissue from both primary surgery and interval debulking surgery, and 12 matched samples with tissue from both primary surgery and surgery for recurrent disease.FR-alpha expression was seen in 81.8% of serous ovarian cancers versus 39.9% of non-serous carcinomas (p <0.001). In matched serous carcinoma samples, no significant change in FR-alpha expression in vital tumor tissue after chemotherapy was observed (p = 0.1). FR-alpha expression was not a prognostic marker of progression free survival (p = 0.8) or overall survival (p = 0.7).FR-alpha was expressed in the majority of serous ovarian tumors, although > 50% of cases showed only weak expression. Chemotherapy did not alter expression rates in remaining vital tumor tissue, indicating that folate-targeted agents may have a place in the treatment for ovarian cancer, before as well as after chemotherapy. Furthermore, FR-alpha status did not influence survival.