Tissue Expression of Sialyl Tn Antigen in Gynecologic Tumors

Abstract

OBJECTIVES: To investigate tissue expression of Sialyl Tn antigen (STN) in gynecologic tumors, and to compare with its appearance in blood circulation. METHODS: Surgical specimens were obtained from 24 patients with malignant gynecologic diseases, including 7 ovarian cancers, 13 cervical cancers, 3 endometrial cancers, and 1 vulval cancer. Control tissues were also obtained at surgery from 28 patients with benign tumors of the ovary or uterus. RESULTS: Anti-STN monoclonal antibody (TKH-2) positively identified 6 (86%) of 7 ovarian cancers, 11 (85%) of 13 cervical squamous-cell carcinomas, but none of 3 endometrial cancers. None of the 28 benign tissues, including 11 ovarian benign tumors, showed positive immunostaining for STN, except 1 with an ovarian chocolate cyst which showed weak staining for STN. No expression was found in normal squamous epithelium distant from the lesion. Serum STN antigen was positive in 4 of 7 ovarian cancers (cutoff = 39 U/ml), but only in 2 of 13 cervical cancers, and none in the 3 endometrial cancers. CONCLUSIONS: These findings indicate different behaviors in the appearance of STN in tumor tissue and blood circulation, and also suggest the possible applicability of STN to immunohistochemical diagnosis of squamous-cell carcinomas.