title: LgR5 expression and cancer stem cell hypothesis: clue to define the true origin of esophageal adenocarcinomas with and without Barrett's esophagus?
abstract: BACKGROUND
  Investigation of the expression of an intestinal stem cell marker in esophageal adenocarcinomas (EAC) with and without Barrett's Esophagus (BE), with respect to a cancer stem cell (CSC) hypothesis.
  
  
  METHODS
  Expression of a putative intestinal stem cell marker LgR5 was analyzed in esophageal cancer specimen (n = 70: 41 EAC with BE, 19 EAC without BE, and n = 10 esophageal squamous-cell carcinomas, ESCC) and in the adenocarcinoma cell line OE-33. Ki-67 and Cdx-2 were co-labelled with LgR5 in double staining experiments. Immunohistochemical expression results were confirmed by RT-PCR and correlated with tumor stage and five-year survival rates.
  
  
  RESULTS
  LgR5was found expressed in 35 of 41 (85%) EAC with BE and in 16 of 19 (81%) EAC without BE. By contrast, LgR5 was not found to be expressed in ESCC. Quantification of immunolabeling showed 15% LgR5+ cells in EAC with BE, 32% LgR5+ cells in adjacent BE and 13% in EAC without BE. Immunofluorescence double staining experiments with LgR5 and Ki-67 revealed a subpopulation (~5%) of proliferating LgR+/Ki-67+ cells. On mRNA-level, expression of LgR5 was higher in BE in comparison to EAC (p = 0.0159). High levels of LgR5 expression in BE associated EAC were associated with poorer survival in univariate analysis.
  
  
  CONCLUSIONS
  The stem cell marker LgR5 is expressed in EAC, irrespective of association with BE, and appears to have negative impact on survival. The subset of proliferating LgR5+ cells (<5%) might resemble rapidly cycling CSCs, which needs to be substantiated in further investigations.
authors.affiliation: Department of General-, Visceral-, Vascular and Pediatric Surgery, University Hospital Wuerzburg, Oberduerrbacher Strasse 6, Wuerzburg, Germany. Rahden_B@chirurgie.uni-wuerzburg.de
authors.forename: Burkhard H A
authors.initials: BH
authors.lastname: von Rahden
authors.forename: Stefan
authors.initials: S
authors.lastname: Kircher
authors.forename: Maria
authors.initials: M
authors.lastname: Lazariotou
authors.forename: Christoph
authors.initials: C
authors.lastname: Reiber
authors.forename: Luisa
authors.initials: L
authors.lastname: Stuermer
authors.forename: Christoph
authors.initials: C
authors.lastname: Otto
authors.forename: Christoph T
authors.initials: CT
authors.lastname: Germer
authors.forename: Martin
authors.initials: M
authors.lastname: Grimm
mesh_terms: D000230:Adenocarcinoma / Q000150:complications / Q000235:genetics* / Q000473:pathology; D000368:Aged; D001471:Barrett Esophagus / Q000150:complications / Q000235:genetics* / Q000473:pathology; D014408:Biomarkers, Tumor / Q000235:genetics*; D002294:Carcinoma, Squamous Cell / Q000150:complications / Q000235:genetics* / Q000473:pathology; D045744:Cell Line, Tumor; D004938:Esophageal Neoplasms / Q000150:complications / Q000235:genetics* / Q000473:pathology; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009367:Neoplasm Staging; D014411:Neoplastic Stem Cells / Q000473:pathology; D012333:RNA, Messenger / Q000235:genetics; D043562:Receptors, G-Protein-Coupled / Q000235:genetics*
chemical_list: D014408:Biomarkers, Tumor; C116884:LGR5 protein, human; D012333:RNA, Messenger; D043562:Receptors, G-Protein-Coupled