title: Immunoreactivity of CD99 in stomach cancer.
abstract: CD99 is characteristically expressed in Ewing's sarcoma/primitive neuroectodermal tumor. Recently its immunoreactivity has also been reported in other tumors. However, the significance of CD99 isoforms expressed in these tumors has not been elucidated. In this study, we evaluated the expression of CD99 isoforms and its relationship with histopathologic parameters in gastric adenocarcinomas. Paraffin sections of 46 gastric adenocarcinomas were stained with an anti-CD99 monoclonal antibody, YG32. Twelve (26.1%) cases of 46 gastric adenocarcinomas showed immunoreactivity to YG32. The CD99 expression was also seen both in non-neoplastic foveolar epithelial cells and infiltrating lymphocytes. In addition, Western blot and RT-PCR analyses revealed that the type I is the predominant isoform of CD99 in non-neoplastic and neoplastic gastric tissues. The CD99 expression was usually seen in the intestinal type adenocarcinoma, while rarely in the diffuse type. The CD99 immunoreactivity decreased in MMP-2-overexpressing adenocarcinomas (p=0.028). Our results suggest that the type I is the major isoform of CD99 expressed in non-neoplastic gastric mucosa and gastric adenocarcinomas and its downregulation in gastric adenocarcinoma may be associated with cellular dedifferentiation and/or MMP-2 overexpression.
authors.affiliation: Department of Pathology, College of Medicine, Hallym University, Chunchon, Korea. jungkc@hallym.ac.kr
authors.forename: Kyeong Cheon
authors.initials: KC
authors.lastname: Jung
authors.forename: Weon Seo
authors.initials: WS
authors.lastname: Park
authors.forename: Young Mee
authors.initials: YM
authors.lastname: Bae
authors.forename: Jang-Hee
authors.initials: JH
authors.lastname: Hahn
authors.forename: Kyuhyoung
authors.initials: K
authors.lastname: Hahn
authors.forename: Hansoo
authors.initials: H
authors.lastname: Lee
authors.forename: Hae Wan
authors.initials: HW
authors.lastname: Lee
authors.forename: Hyung-Jin
authors.initials: HJ
authors.lastname: Koo
authors.forename: Hai-Jeong
authors.initials: HJ
authors.lastname: Shin
authors.forename: Hyung Sik
authors.initials: HS
authors.lastname: Shin
authors.forename: Young Euy
authors.initials: YE
authors.lastname: Park
authors.forename: Seong Hoe
authors.initials: SH
authors.lastname: Park
mesh_terms: D000071443:12E7 Antigen; D000230:Adenocarcinoma / Q000276:immunology* / Q000473:pathology; D000328:Adult; D000368:Aged; D015703:Antigens, CD / Q000032:analysis* / Q000235:genetics; D015815:Cell Adhesion Molecules / Q000032:analysis* / Q000235:genetics; D005260:Female; D005753:Gastric Mucosa / Q000166:cytology / Q000276:immunology; D006801:Humans; D008297:Male; D020782:Matrix Metalloproteinases / Q000378:metabolism; D008875:Middle Aged; D020033:Protein Isoforms / Q000032:analysis / Q000235:genetics; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D013274:Stomach Neoplasms / Q000276:immunology* / Q000473:pathology
chemical_list: D000071443:12E7 Antigen; D015703:Antigens, CD; C061828:CD99 protein, human; D015815:Cell Adhesion Molecules; D020033:Protein Isoforms; D012333:RNA, Messenger; D020782:Matrix Metalloproteinases