Ovarian tumors with functioning stroma. An immunohistochemical study of 100 cases with human chorionic gonadotropin monoclonal and polyclonal antibodies.

The frequency of stromal activation and its possible relation to human chorionic gonadotropin (HCG) or HCG-like secretion by tumor cells has been studied in 100 nonselected, consecutive, primary and secondary ovarian neoplasms. Stromal luteinization was present in 13 cases and stromal condensation in 16. The types of tumors most commonly associated with activation of the ovarian stroma were as follows: mucinous tumors (11 cases), endometrioid and clear cell tumors (six cases), and metastasis of gastrointestinal adenocarcinomas (six cases). We used to commercial polyclonal antibodies as well as four more specific monoclonal antibodies (FBT-10, FBT-11, FB-12, and FB-13). Immunohistochemical studies (peroxidase-antiperoxidase [PAP]) yielded the following staining results: polyclonal HCG and/or polyclonal beta-HCG positivity was present in 22 tumors (12 had an activated stroma and ten an inactive one). In addition, 44 tumors were positive for FBT-10, FBT-11, FB-12, and FB-13 monoclonal antibodies (18 showed activation of the stroma, which was inactive in 26). Only 11 of the 56 HCG-negative tumors exhibited activation of the stroma. Thus, positivity for HCG was more frequently found in tumors with morphologically active stroma than in those with an inactive one. However, five HCG polyclonal positive tumors--three of them exhibiting activation of the stroma--were negative for the monoclonal antibodies. It appears that HCG plays a role in the activation of the stroma of some ovarian tumors, yet, HCG-like substances as well as other factors may also be involved.