Objective: With neoplastic progression, the precursor of epithelial ovarian cancers, the ovarian surface epithelium (OSE), undergoes Mullerian differentiation, usually of the oviductal type. The aim of this study was to examine the expression of oviduct-specific glycoprotein (OGP), a marker of normal oviductal epithelium, for use as a diagnostic or prognostic marker for ovarian cancer.
Methods and materials: Immunohistochemical analysis for OGP was performed on 389 ovarian tumors and 19 normal ovaries, as well as 433 cases representing 45 normal tissues and 51 benign and malignant tumor types from 37 different tissues.
Results: OGP was absent in OSE but present in 28 of 31 epithelial inclusion cysts, 13 of 14 (93%) serous cystadenomas, and 46 of 65 (71%) serous borderline tumors. Of 183 serous adenocarcinomas, 26 (14%) were positive for OGP, including 5 of 8 (63%) grade I, 7 of 41 (17%) grade II, and 14 of 134 (10%) grade III carcinomas. OGP was found in 7 of 14 (50%) borderline and 9 of 15 (60%) malignant mucinous ovarian tumors and in 10 of 39 (26%) endometrioid adenocarcinomas. The localization of OGP in the lumen of glandular structures suggested that it was secreted. OGP was absent in 41 of 45 normal tissues and positive in oviduct and, weakly, in salivary gland, duodenum, and ileum. Forty-six types of nongynecologic tumors were negative, as were gynecologic neoplasms except for 2 of 47 cervical and 3 of 56 endometrial carcinomas.
Conclusion: OGP is a new tubal differentiation marker which characterizes benign and borderline serous neoplasms and may indicate early events in ovarian carcinogenesis.