title: Keratin 7 expression as an early marker of reflux-related columnar mucosa without intestinal metaplasia in the esophagus.
abstract: BACKGROUND
  The role of Barrett esophagus in carcinogenesis is widely accepted, but the significance of esophageal columnar mucosa without histological intestinal metaplasia, known as columnar-lined esophagus, is debated.
  
  
  METHODS
  We studied 128 patients free of Helicobacter pylori with reflux-related symptoms and columnar mucosa in the esophagus at endoscopy, 106 patients with Barrett esophagus (referred to as the Barrett group) and 22 patients without intestinal metaplasia (columnar group). Samples from 20 subjects free of H. pylori were used as controls. Immunostaining for keratin 7 (KRT7), keratin 20 (KRT20), caudal type homeobox 2 (CDX2), mucin 2, oligomeric mucus/gel-forming (MUC2), and tumor protein p53 (TP53) was assessed.
  
  
  RESULTS
  Samples taken 1 cm above the gastroesophageal junction showed KRT7 staining in all cases in the Barrett and columnar groups and none in the control group. Immunostaining for TP53 was absent in the control group, and more frequent in the columnar group (7, 31.8%) compared with the Barrett group (14, 13.2%, P=0.033). In the columnar group, low grade dysplasia and TP53 expression was seen in 7 of 22 biopsy specimens (31.8%) at baseline and in 4 additional specimens after 2 years, for a total of 11 specimens (50.0%).
  
  
  CONCLUSIONS
  The expression of KRT7 might help to explain the pathological, reflux-related nature of columnar-lined esophagus, as aberrant expression in a very early stage of the multistep Barrett esophagus progression. Expression of KRT7 may occur in basal glandular cells as a result of their multipotentiality and susceptibility to immunophenotype changes induced by reflux.
authors.affiliation: Department of Histopathology, University of Palermo, Italy. huntermat@libero.it
authors.forename: Daniela
authors.initials: D
authors.lastname: Cabibi
authors.forename: Eugenio
authors.initials: E
authors.lastname: Fiorentino
authors.forename: Gianni
authors.initials: G
authors.lastname: Pantuso
authors.forename: Achille
authors.initials: A
authors.lastname: Mastrosimone
authors.forename: Cosimo
authors.initials: C
authors.lastname: Callari
authors.forename: Matilde
authors.initials: M
authors.lastname: Cacciatore
authors.forename: Maria
authors.initials: M
authors.lastname: Campione
authors.forename: Francesco
authors.initials: F
authors.lastname: Aragona
mesh_terms: D001471:Barrett Esophagus / Q000378:metabolism / Q000382:microbiology / Q000473:pathology*; D015415:Biomarkers / Q000378:metabolism*; D016022:Case-Control Studies; D004943:Esophagogastric Junction / Q000378:metabolism* / Q000473:pathology; D016480:Helicobacter pylori / Q000302:isolation & purification; D006801:Humans; D007422:Intestines / Q000473:pathology*; D053552:Keratin-7 / Q000378:metabolism*; D008679:Metaplasia
chemical_list: D015415:Biomarkers; C507497:KRT7 protein, human; D053552:Keratin-7