title: Assessment of the validity of a multigene analysis in the diagnostics of inflammatory bowel disease.
abstract: OBJECTIVE
  The findings of a previous multigene study indicated that the expression of a panel of seven specific genes had strong differential power regarding inflammatory bowel disease (IBD) versus non-IBD, as well as ulcerative colitis (UC) versus Crohn's disease (CD). This prospective confirmatory study based on an independent patient cohort from a national Danish IBD centre was conducted in an attempt to verify these earlier observations.
  
  
  METHODS
  A total of 119 patients were included in the study (CD, UC and controls). Three mucosal biopsies were retrieved from the left side of the colon of each patient. RNA was extracted, and RT-PCR was performed to retain expression profiles from the seven selected genes. Expression data from the training set (18 CD, 20 UC and 20 controls) were used to build a classification model, using quadratic discriminant analysis, and data from the test set (20 CD, 21 UC and 20 controls) were used to test the validity of the model.
  
  
  RESULTS
  The present investigation did not confirm the previous observation that a panel of seven specific genes is able to distinguish between patients with CD and UC, whereas the discriminative power for IBD versus control subjects was substantiated.
  
  
  CONCLUSIONS
  Our results fail to demonstrate that the previously identified seven-gene classification model is able to discriminate between CD and UC but suggest that the gene panel merely discriminates between inflamed and noninflamed colonic tissue. Thus, a reliable and simple diagnostic tool is still warranted for optimal diagnosis and treatment of patients with IBD, especially the subgroup with unclassified disease.
authors.affiliation: Department of Gastroenterology, Medical Section, Herlev Hospital, University of Copenhagen, Copenhagen, Denmark; Department of Cellular & Molecular Medicine, The Panum Institute, University of Copenhagen, Copenhagen, Denmark.
authors.forename: J T
authors.initials: JT
authors.lastname: Bjerrum
authors.forename: C
authors.initials: C
authors.lastname: Nyberg
authors.forename: J
authors.initials: J
authors.lastname: Olsen
authors.forename: O H
authors.initials: OH
authors.lastname: Nielsen
mesh_terms: D000328:Adult; D000581:Amidohydrolases / Q000235:genetics; D026905:Amino Acid Transport Systems; D026921:Amino Acid Transport Systems, Neutral / Q000235:genetics; D027321:Anion Transport Proteins / Q000235:genetics; D019540:Area Under Curve; D054360:Chemokine CXCL1 / Q000235:genetics; D003093:Colitis, Ulcerative / Q000175:diagnosis* / Q000235:genetics; D003424:Crohn Disease / Q000175:diagnosis* / Q000235:genetics; D005260:Female; D058851:GPI-Linked Proteins / Q000235:genetics; D015870:Gene Expression / Q000235:genetics; D005819:Genetic Markers / Q000235:genetics; D006801:Humans; D037181:Lectins, C-Type / Q000235:genetics; D008297:Male; D020783:Matrix Metalloproteinase 7 / Q000235:genetics; D008565:Membrane Proteins / Q000235:genetics; D000073718:Pancreatitis-Associated Proteins; D011446:Prospective Studies; D060888:Real-Time Polymerase Chain Reaction; D000076988:Sulfate Transporters
chemical_list: D026905:Amino Acid Transport Systems; D026921:Amino Acid Transport Systems, Neutral; D027321:Anion Transport Proteins; D054360:Chemokine CXCL1; D058851:GPI-Linked Proteins; D005819:Genetic Markers; D037181:Lectins, C-Type; D008565:Membrane Proteins; C509768:PDZK1IP1 protein, human; D000073718:Pancreatitis-Associated Proteins; C428528:REG4 protein, human; C089651:SLC26A2 protein, human; C503995:SLC6A14 protein, human; D000076988:Sulfate Transporters; C060932:MMP7 protein, human; D020783:Matrix Metalloproteinase 7; D000581:Amidohydrolases; C022314:pantetheinase
keywords: Crohn's disease; colonic mucosal biopsy; diagnostics; gene expression; ulcerative colitis