Oviduct-specific glycoprotein (OVGP1), a new serum biomarker for the detection of ovarian cancer

4451 Ovarian carcinomas are the most lethal tumors of the female genital tract because most are detected late in the disease course. Our previous immunohistochemical study, using a polyclonal antibody, showed that oviduct-specific glycoprotein (OVGP1), normally a secreted and glycosylated protein of the oviduct, is aberrantly expressed and secreted in low grade ovarian epithelial neoplasias, suggesting that it may be detectable in the serum of women with such tumors. We generated a monoclonal antibody, clone OGP 7E10, to recombinant OVGP1, which recognizes the C-terminal region of the protein. It recognizes OVGP1 in conditioned medium at a molecular weight of 110-130 kDa and binds specifically to secretory epithelial cells of the mid- to late-proliferative phase oviduct. Immunohistochemical analysis of an ovarian tumor tissue array using OGP 7E10 demonstrated OVGP1 in 6/10 (60%) low grade serous carcinomas (LGSC), 168/185 (91%) high grade serous carcinomas (HGSC), 96/108 (89%) endometrioid carcinomas, 20/23 (87%) mucinous carcinomas and 102/116 (88%) clear cell carcinomas. Analysis with a Kaplan-Meier curve and log-rank statistics showed that positive OVGP1 staining in HGSCs was associated with a more favorable outcome (p