The value of tumour marker CA 125 in surgical pathology

CA 125 is a tumour marker located primarily on non-mucinous epithelial ovarian tumours and which is recognized by the monoclonal antibody OC 125. In this study the value of CA 125 in surgical pathology was assessed. In fresh frozen material, the expression of CA 125 was demonstrated in 82% of 83 epithelial ovarian neoplasms using the indirect immunoperoxidase technique. In addition, all adenocarcinomas of cervix (n = 5) and endometrium (n = 15) tested expressed CA 125, and 25 of 111 (22%) non-gynaecological malignant tumours were positive. The positive cases included 20 breast carcinomas, one carcinoma of the stomach and one of the colon. Using a commercial kit on routinely fixed, paraffin embedded material, CA 125 positivity was demonstrated in 29 of 36 (80%) serous cystadenocarcinomas after pronase pre-treatment of the sections, in contrast to 100% (n = 25) positivity on frozen tissue sections. CA 125 can, therefore, be demonstrated in routinely fixed paraffin embedded material, although the number of positive results is less than in fresh frozen sections.