Immunohistochemical detection of CA-125 and carcinoembryonic antigen in ovarian tumors in relation to corresponding preoperative serum levels.

The immunohistochemically detectable expression of CA-125 and CEA in ovarian tumor tissue from 187 patients was related to corresponding preoperative serum levels. A strong positive association between tissue expression and the serum level of both the CA-125 and CEA antigens was found in cases of invasive epithelial ovarian carcinoma. However, this relationship was absent for CA-125 in borderline cases and patients with benign ovarian tumors, although the antigen frequently was detectable in them. The presence of ascites could be verified in 3 of 10 cases with benign CA-125 negative tumors, but elevated CA-125 levels in serum. 'False negative' CA-125 levels were found in 6 borderline and 7 true invasive carcinoma cases despite positive tissue staining. Eight of those patients had limited stage I disease. The data suggests that although the tissue expression of the CA-125 and CEA antigens in invasive ovarian carcinoma has an important influence in the corresponding serum level, compartment barriers and low cell turnover in benign, and to a lesser extent borderline, cases result in low serum levels. In addition, other factors influence serum levels of CA-125, such as secondary peritoneal response with or without ascites, which may cause 'falsely elevated' CA-125 results in benign disease.