title: Dedifferentiation precedes invasion in the progression from Barrett's metaplasia to esophageal adenocarcinoma.
abstract: OBJECTIVE
  Adenocarcinoma arises in Barrett's esophagus by progression from metaplasia to cancer through grades of dysplasia. Our aim in this exploratory study was to characterize the broad changes in gene expression that underlie this histologic progression to cancer and assess the potential for using these gene expression changes as a marker predictive of malignant progression in Barrett's epithelium.
  
  
  METHODS
  Microarray analysis was used to obtain individual gene expression profiles from endoscopic biopsies of nine esophageal adenocarcinomas and the Barrett's epithelia from which three of the cancers had arisen. Pooled samples from the Barrett's epithelia of six patients without cancer or dysplasia served as a reference.
  
  
  RESULTS
  Barrett's epithelia from which cancer had arisen differed from the reference Barrett's epithelia primarily by underexpression of genes, many of which function in governing cell differentiation. These changes in gene expression were found even in those specimens of Barrett's epithelia from which cancer had arisen that lacked dysplasia. Each cancer differed from the Barrett's epithelium from which it had arisen primarily by an overexpression of genes, many of which were associated with tissue remodeling and invasiveness. Cancers without identifiable Barrett's epithelium differed from cancers that had arisen from a Barrett's epithelium by having an even greater number of these overexpressed genes.
  
  
  CONCLUSIONS
  Histologic progression from Barrett's epithelium to cancer is associated with a gradient of increasing changes in gene expression characterized by an early loss of gene function governing differentiation that begins before histologic change; gain in function of genes related to remodeling and invasiveness follows later. This correlation of histologic progression with increasing changes in gene expression suggests that gene expression changes in biopsies taken from Barrett's epithelium potentially could serve as a marker for neoplastic progression that could be used to predict risk for developing cancer.
authors.affiliation: Gastrointestinal Tumor Program, H. Lee Moffitt Cancer Center and Research Institute, University of South Florida, Tampa, Florida 33612, USA. helmjf@moffitt.usf.edu
authors.forename: James
authors.initials: J
authors.lastname: Helm
authors.forename: Steven A
authors.initials: SA
authors.lastname: Enkemann
authors.forename: Domenico
authors.initials: D
authors.lastname: Coppola
authors.forename: James S
authors.initials: JS
authors.lastname: Barthel
authors.forename: Scott T
authors.initials: ST
authors.lastname: Kelley
authors.forename: Timothy J
authors.initials: TJ
authors.lastname: Yeatman
mesh_terms: D000230:Adenocarcinoma / Q000235:genetics* / Q000473:pathology; D001471:Barrett Esophagus / Q000235:genetics* / Q000473:pathology; D002454:Cell Differentiation / Q000235:genetics; D016000:Cluster Analysis; D018450:Disease Progression; D004848:Epithelium / Q000378:metabolism / Q000473:pathology; D004938:Esophageal Neoplasms / Q000235:genetics* / Q000473:pathology; D020869:Gene Expression Profiling; D015972:Gene Expression Regulation, Neoplastic / Q000235:genetics; D006801:Humans; D008679:Metaplasia / Q000235:genetics; D008954:Models, Biological; D009361:Neoplasm Invasiveness / Q000235:genetics; D020411:Oligonucleotide Array Sequence Analysis; D011379:Prognosis