title: Decreased expression of gastrokine 1 and the trefoil factor interacting protein TFIZ1/GKN2 in gastric cancer: influence of tumor histology and relationship to prognosis.
abstract: OBJECTIVE
  Transcriptional profiling showed decreased expression of gastrokine 1 (GKN1) and the related trefoil factor interacting protein (TFIZ1/GKN2) in Helicobacter pylori infection. Decreased GKN1 and GKN2 mRNA expression has been reported in gastric adenocarcinoma. We have examined GKN1 and GKN2 protein expression in a large gastric cancer series, correlated expression with tumor subtype, and evaluated their utility as prognostic biomarkers.
  
  
  METHODS
  GKN1, GKN2, and the trefoil factors TFF1 and TFF3 were examined in tissue microarrays from 155 distal gastric adenocarcinomas. Immunohistochemical expression was correlated with clinical outcome. GKN1 and GKN2 expression was measured by real-time PCR and Western analysis in samples of gastric cancer and adjacent nonneoplastic mucosa.
  
  
  RESULTS
  GKN1 was lost in 78% of diffuse and 42% of intestinal cancers (P < 0.0001, diffuse versus intestinal). GKN2 expression was lost in 85% of diffuse and 54% of intestinal type cancers (P < 0.002). GKN1 and GKN2 down-regulation were confirmed by Western and real-time PCR analysis. Loss of either protein was associated with significantly worse outcome in intestinal-type tumors by univariate analysis; and GKN2 loss remained a predictor of poor outcome in multivariate analysis (P < 0.033). TFF1 was lost in >70%, and TFF3 was expressed in approximately 50% of gastric cancers.
  
  
  CONCLUSIONS
  Loss of GKN1 and GKN2 expression occurs frequently in gastric adenocarcinomas, especially in the diffuse subtype. GKN1 and GKN2 loss are associated with shorter overall survival in the intestinal subtype.
authors.affiliation: Department of Medicine, Gastroenterology Division, Rhode Island Hospital, 593 Eddy Street, APC 414, Providence, RI 02903, USA. Steven_Moss@Brown.edu
authors.forename: Steven F
authors.initials: SF
authors.lastname: Moss
authors.forename: Jin-Woo
authors.initials: JW
authors.lastname: Lee
authors.forename: Edmond
authors.initials: E
authors.lastname: Sabo
authors.forename: Anna K
authors.initials: AK
authors.lastname: Rubin
authors.forename: John
authors.initials: J
authors.lastname: Rommel
authors.forename: Bruce R
authors.initials: BR
authors.lastname: Westley
authors.forename: Felicity E B
authors.initials: FE
authors.lastname: May
authors.forename: John
authors.initials: J
authors.lastname: Gao
authors.forename: Patricia A
authors.initials: PA
authors.lastname: Meitner
authors.forename: Rose
authors.initials: R
authors.lastname: Tavares
authors.forename: Murray B
authors.initials: MB
authors.lastname: Resnick
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002352:Carrier Proteins / Q000096:biosynthesis*; D005260:Female; D020869:Gene Expression Profiling; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D007150:Immunohistochemistry; D008297:Male; D008875:Middle Aged; D036361:Peptide Hormones / Q000096:biosynthesis* / Q000502:physiology; D011379:Prognosis; D013274:Stomach Neoplasms / Q000175:diagnosis / Q000378:metabolism* / Q000473:pathology; D016896:Treatment Outcome
chemical_list: D002352:Carrier Proteins; C477000:GKN1 protein, human; C503073:GKN2 protein, human; D036361:Peptide Hormones