Antigen CA125 in tumor tissue and serum from patients with adenocarcinoma of the ovary.

The presence of cancer antigen CA125 has been assessed immunohistologically in formalin-fixed tumor tissue and immunoradiometrically in serum from 41 women with residual epithelial ovarian carcinoma after diagnostic laparotomy. CA125 was detected in tumor tissue from the majority of patients (34/41), including those with normal serum levels (15/18). The major determinant of serum CA125 concentration appears to be the size of the residual tumor. The results suggest that in the majority of patients with small residual tumor masses and normal postoperative serum antigen levels, progressive disease may well be associated with increasing serum CA125 levels.