title: Altered expression and localization of connexin32 in human and murine gastric carcinogenesis.
abstract: BACKGROUND
  Intercellular communication via gap junctions, composed of protein subunits called connexins (Cxs), plays a key role in controlling cell growth, differentiation and carcinogenesis. Impaired gap junctional intercellular communication has been reported in various cancers and diseases.
  
  
  OBJECTIVE
  We investigated Cx32 expression patterns and semiquantitatively assessed Cx32 expression in cancers and preneoplastic lesions. To determine if cell proliferation is correlated with Cx32 expression, we evaluated Ki67 expression in a gastric cancer mouse model.
  
  
  METHODS
  In human and mouse, normal stomach and gastric adenocarcinoma tissues were used for immunohistochemical analyses.
  
  
  RESULTS
  Cx32 was detected at cell-cell (intercellular) contact points in normal cells and exhibited punctate intercellular and intracytoplasmic staining in cancer cells. The frequency of Cx32 loss of expression was significantly higher in human adenocarcinomas than in normal stomach. As tumor cells were less differentiated, Cx32 expression levels and intercellular and intracytoplasmic staining were also significantly lower. The Cx32 expression pattern in the mouse gastric cancer model was similar in several important respects to that of human. In mucous metaplasia of the mouse stomach, Cx32 was mainly expressed in the cytoplasm of epithelial cells. There was also an inverse correlation between Cx32 expression and cell proliferation in mouse tumors. However, there was no difference in the levels of Cx32 mRNA between normal and cancerous tissues.
  
  
  CONCLUSIONS
  These findings suggest that altered Cx32 expression, a loss of intercellular Cx32 and a gain of intracytoplasmic Cx32 in the form of punctate "dot", plays an important role in the formation of gastric adenocarcinomas.
authors.affiliation: Laboratory of Veterinary Pathology, College of Veterinary Medicine, Seoul National University, 599 Gwanak-ro, Gwanak-gu, Seoul, 151-742, Korea. hyang104@snu.ac.kr
authors.forename: Hyang
authors.initials: H
authors.lastname: Jee
authors.forename: Ki Taek
authors.initials: KT
authors.lastname: Nam
authors.forename: Hyo-Jung
authors.initials: HJ
authors.lastname: Kwon
authors.forename: Sang-Uk
authors.initials: SU
authors.lastname: Han
authors.forename: Dae-Yong
authors.initials: DY
authors.lastname: Kim
mesh_terms: D000818:Animals; D017630:Connexins / Q000235:genetics / Q000378:metabolism*; D015972:Gene Expression Regulation, Neoplastic / Q000502:physiology*; D006801:Humans; D019394:Ki-67 Antigen / Q000235:genetics / Q000378:metabolism; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D013274:Stomach Neoplasms / Q000378:metabolism*; D000097002:Gap Junction beta-1 Protein
chemical_list: D017630:Connexins; D019394:Ki-67 Antigen; D012333:RNA, Messenger; D000097002:Gap Junction beta-1 Protein