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Serum folate receptor alpha as a biomarker for ovarian cancer: Implications for diagnosis, prognosis and predicting its local tumor expression
Author(s) -
Kurosaki Akira,
Hasegawa Kosei,
Kato Tomomi,
Abe Kenji,
Hanaoka Tatsuya,
Miyara Akiko,
O'Shannessy Daniel J.,
Somers Elizabeth B.,
Yasuda Masanori,
Sekino Tetsuo,
Fujiwara Keiichi
Publication year - 2015
Publication title -
international journal of cancer
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.475
H-Index - 234
eISSN - 1097-0215
pISSN - 0020-7136
DOI - 10.1002/ijc.29937
Subject(s) - ovarian cancer , medicine , biomarker , cancer , colorectal cancer , oncology , immunohistochemistry , pathology , biology , biochemistry
Folate receptor alpha (FRA) is a GPI‐anchored glycoprotein and encoded by the FOLR1 gene. High expression of FRA is observed in specific malignant tumors of epithelial origin, including ovarian cancer, but exhibits very limited normal tissue expression, making it as an attractive target for the ovarian cancer therapy. FRA is known to shed from the cell surface into the circulation which allows for its measurement in the serum of patients. Recently, methods to detect the soluble form of FRA have been developed and serum FRA (sFRA) is considered a highly promising biomarker for ovarian cancer. We prospectively investigated the levels of sFRA in patients clinically suspected of having malignant ovarian tumors. A total of 231 patients were enrolled in this study and analyzed for sFRA as well as tumor expression of FRA by immunohistochemistry. High sFRA was predominantly observed in epithelial ovarian cancer patients, but not in patients with benign or borderline gynecological disease or metastatic ovarian tumors from advanced colorectal cancers. Levels of sFRA were highly correlated to clinical stage, tumor grade and histological type and demonstrated superior accuracy for the detection of ovarian cancer than did serum CA125. High sFRA was significantly associated with shorter progression‐free survival in both early and advanced ovarian cancer patients. Finally, tumor FRA expression status was strongly correlated with sFRA levels. Taken together, these data suggest that sFRA might be a useful noninvasive serum biomarkers for future clinical trials assessing FRA‐targeted therapy.