title: Different levels of sialyl-Tn antigen expressed on MUC16 in patients with endometriosis and ovarian cancer.
abstract: 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.
  
  
  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-Le, 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.
authors.affiliation: Department of Molecular Biosciences, Faculty of Life Sciences, Kyoto Sangyo University, Kamigamo-Motoyama, Kyoto, Japan.
authors.forename: Kaoru
authors.initials: K
authors.lastname: Akita
authors.forename: Shuhei
authors.initials: S
authors.lastname: Yoshida
authors.forename: Yuzuru
authors.initials: Y
authors.lastname: Ikehara
authors.forename: Sayumi
authors.initials: S
authors.lastname: Shirakawa
authors.forename: Munetoyo
authors.initials: M
authors.lastname: Toda
authors.forename: Mizue
authors.initials: M
authors.lastname: Inoue
authors.forename: Jo
authors.initials: J
authors.lastname: Kitawaki
authors.forename: Hayao
authors.initials: H
authors.lastname: Nakanishi
authors.forename: Hisashi
authors.initials: H
authors.lastname: Narimatsu
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Nakada
mesh_terms: D000328:Adult; D000368:Aged; D015295:Antigens, Tumor-Associated, Carbohydrate / Q000378:metabolism*; D001202:Ascitic Fluid / Q000378:metabolism*; D014408:Biomarkers, Tumor / Q000378:metabolism*; D015153:Blotting, Western; D018394:CA-125 Antigen / Q000378:metabolism*; D017077:Culture Media, Conditioned / Q000494:pharmacology; D004715:Endometriosis / Q000175:diagnosis / Q000378:metabolism*; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D006801:Humans; D007124:Immunoenzyme Techniques; D008565:Membrane Proteins / Q000378:metabolism*; D008875:Middle Aged; D060787:Neoplasm Grading; D009367:Neoplasm Staging; D009844:Oligosaccharides / Q000378:metabolism*; D010051:Ovarian Neoplasms / Q000175:diagnosis / Q000378:metabolism*; D011379:Prognosis; D014407:Tumor Cells, Cultured
chemical_list: D015295:Antigens, Tumor-Associated, Carbohydrate; D014408:Biomarkers, Tumor; D018394:CA-125 Antigen; D017077:Culture Media, Conditioned; C451759:MUC16 protein, human; D008565:Membrane Proteins; D009844:Oligosaccharides; C055491:sialosyl-Tn antigen; C058981:sialyl-Le(a) oligosaccharide