The study deals with the occurrence of cancer antigen 125 (CA 125) in the normal and neoplastic uterine cervix, endometrium and fallopian tube and its applicability as a tumour marker. CA 125 concentrations were measured in 52 secretion specimens, in cytosol fractions of 97 tissue biopsies and in serum from 47 women with nonmalignant disorders and from 334 patients with carcinomas. High quantities of CA 125 (780-454860 U/ml) were detected in cervical mucus, intra-uterine and tubal fluid, exceeding those in the corresponding serum samples by factors of up to 2000. CA 125 concentrations were 9-53 fold higher in cytosol fractions of normal and neoplastic glandular epithelia of the endocervix and endometrium than in those of cervical squamous epithelia and the cervical wall. Despite similarly high antigen concentrations in normal glandular epithelia and adenocarcinomas serum levels elevated to above 65 U/ml were only found in patients with malignant tumours. The positivity rates in serum increased with tumour extent and were 0-43% for primary and 63-79% for recurrent cervical, endometrial and tubal adenocarcinomas. During long-term follow-up, CA 125 serum concentrations were concordant with the clinical course in 10 out of 11 patients with progressive carcinomas. According to these results, the release of CA 125 into the peripheral blood is apparently dependent on the infiltrative growth and the mass of the tumour rather than on the local tissue concentrations. The clinical use of CA 125 is limited to the detection of advanced adenocarcinomas of the Müllerian duct.
