title: Expression of claudins 7 and 18 in pancreatic ductal adenocarcinoma: association with features of differentiation.
abstract: OBJECTIVE
  This study was undertaken to evaluate the expression of claudins 7 and 18 in pancreatic ductal adenocarcinoma.
  
  
  RESULTS
  Material tested included 111 operated samples and 47 additional biopsy samples consisting of 26 cases of pancreatitis, 3 cases of pancreatic intraepithelial neoplasia and 18 ductal adenocarcinomas. Samples were stained with antibodies to claudins 7 and 18 and analysed for membranous and cytoplasmic expression. Membrane bound claudin 7 and 18 expression was detected in 62 of 105 (59%) and 78 of 111 (70%) cases, respectively. Membrane bound claudin 7 and 18 were associated with large or intermediate neoplastic ducts (p=0.01, p=0.002, respectively). Well differentiated pancreatic adenocarcinomas displayed more cases with membrane bound claudin 7 or 18 immunopositivity (p=0.003, p=0.03, respectively). All pancreatic intraepithelial neoplasias studied expressed membrane bound claudin 18. Membrane bound claudin 7 or 18 positivity was not associated with survival (p=0.17, p=0.98). In the biopsy cases membrane bound claudin 18 had 100% specificity and 51% sensitivity for a tumour marker.
  
  
  CONCLUSIONS
  Claudin 7 and 18 expression is related to gland size of neoplastic cells and is especially found in tumours with intermediate and large ducts and well differentiated tumours. Membrane bound claudin 18, when present, is a useful marker for diagnosis of pancreatic cancer. Claudins 7 and 18 were not associated with patient survival or spread of tumours.
authors.affiliation: Department of Pathology and Forensic Medicine, Institute of Clinical Medicine, School of Medicine, University of Eastern Finland, Cancer Center of Eastern Finland, Kuopio, Finland. ylermi.soini@uef.fi
authors.forename: Y
authors.initials: Y
authors.lastname: Soini
authors.forename: A
authors.initials: A
authors.lastname: Takasawa
authors.forename: M
authors.initials: M
authors.lastname: Eskelinen
authors.forename: P
authors.initials: P
authors.lastname: Juvonen
authors.forename: V
authors.initials: V
authors.lastname: Kärjä
authors.forename: T
authors.initials: T
authors.lastname: Hasegawa
authors.forename: M
authors.initials: M
authors.lastname: Murata
authors.forename: S
authors.initials: S
authors.lastname: Tanaka
authors.forename: T
authors.initials: T
authors.lastname: Kojima
authors.forename: N
authors.initials: N
authors.lastname: Sawada
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D014408:Biomarkers, Tumor / Q000378:metabolism*; D002278:Carcinoma in Situ / Q000378:metabolism / Q000473:pathology; D021441:Carcinoma, Pancreatic Ductal / Q000378:metabolism* / Q000473:pathology; D002454:Cell Differentiation; D002462:Cell Membrane / Q000378:metabolism / Q000473:pathology; D057167:Claudins / Q000378:metabolism*; D003593:Cytoplasm / Q000378:metabolism / Q000473:pathology; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010190:Pancreatic Neoplasms / Q000378:metabolism* / Q000473:pathology; D010195:Pancreatitis / Q000378:metabolism / Q000473:pathology
chemical_list: D014408:Biomarkers, Tumor; C486683:CLDN18 protein, human; C473255:CLDN7 protein, human; D057167:Claudins