RT Journal Article SR Electronic T1 Different Levels of Sialyl-Tn Antigen Expressed on MUC16 in Patients With Endometriosis and Ovarian Cancer JF International Journal of Gynecologic Cancer JO Int J Gynecol Cancer FD BMJ Publishing Group Ltd SP 531 OP 538 DO 10.1097/IGC.0b013e3182473292 VO 22 IS 4 A1 Kaoru Akita A1 Shuhei Yoshida A1 Yuzuru Ikehara A1 Sayumi Shirakawa A1 Munetoyo Toda A1 Mizue Inoue A1 Jo Kitawaki A1 Hayao Nakanishi A1 Hisashi Narimatsu A1 Hiroshi Nakada YR 2012 UL http://ijgc.bmj.com/content/22/4/531.abstract AB Objective Although CA125 antigen is a useful marker for ovarian cancer, its expression is also elevated in endometriosis. The purpose of this study was to develop an assay method for evaluating differentially glycosylated MUC16 (CA125 core protein) in patients with endometriosis and ovarian cancer.Materials and Methods We prepared MUC16-enriched fractions from peritoneal fluid of patients with endometriosis and conditioned medium of ovarian carcinoma-3 cells by gel filtration, and evaluated the expression of sialyl-Lea, Tn, and sialyl-Tn antigens by dot blot analysis. A sandwich enzyme-linked immunosorbent assay was developed to measure the level of sialyl-Tn antigen expressed on MUC16 (sTn/MUC16). The level of sTn/MUC16 was compared between patients with endometriosis (n = 21) and ovarian cancer (n = 36) and in ovarian cancers with different clinical diagnostic criteria. Furthermore, distribution of MUC16 and sialyl-Tn antigen in ovarian cancer tissues was observed immunohistochemically.Results Sialyl-Tn antigen was markedly detectable in the MUC16-enriched fractions from conditioned medium of ovarian carcinoma-3 cells but negligible in those from the peritoneal fluid of the patients with endometriosis. The level of sTn/MUC16 determined by a sandwich enzyme-linked immunosorbent assay was significantly higher in the patients with ovarian cancer than that in the patients with endometriosis (P < 0.001). An elevated level of sTn/MUC16 was detected in 44% of the patients with ovarian cancer but not all the patients with endometriosis. This level increased more prominently in the patients with ovarian cancer than that of MUC16 as both the clinical stage and cytological grade advanced. An elevated level of sTn/MUC16 was frequently found in the patients with serous and endometrioid carcinomas. Consistent with this, sialyl-Tn antigen was colocalized with MUC16 in serous and endometrioid ovarian cancer tissues.Conclusions Estimation of the sTn/MUC16 level may be useful for discriminating endometriosis from ovarian cancer and for evaluating the clinical stage, cytological grade, and histological type of ovarian cancer.