title: Cytoplasmic expression of LGR5 in pancreatic adenocarcinoma.
abstract: BACKGROUND
  CD133 has been identified as a cancer stem cell marker for pancreatic ductal adenocarcinoma. Although leucine-rich-repeat-containing G-protein-coupled receptor 5 (LGR5), a marker of intestinal stem cells, has been shown to be on a higher level of the stem cell hierarchy than CD133, the expression and function of LGR5 in pancreatic cancer tissue remains unclear. This study investigated tissue expression of LGR5 and CD133 in resected pancreatic cancer tissue.
  
  
  METHODS
  LGR5 and CD133 expression was immunohistochemically examined in 9 patients with pancreatic ductal adenocarcinoma who underwent resection.
  
  
  RESULTS
  LGR5 was expressed in the cytoplasm of pancreatic cancer cells in 4 of 9 cases. CD133 was not detected in cancerous tissue. In non-neoplastic tissue, LGR5 was expressed in the basolateral membrane of a subset of endocrine cells. Conversely, CD133 was expressed in the apical membrane of small duct cells. Co-localization of LGR5 and CD133 was not found in either neoplastic or non-neoplastic tissue. LGR5 expression in pancreatic cancer cells showed no statistically significant correlation with survival after surgery.
  
  
  CONCLUSIONS
  We have demonstrated that LGR5 is expressed in the cytoplasm of pancreatic adenocarcinoma cells, and the basolateral membrane of a subset of endocrine cells of the human pancreas. Further investigation is required to clarify any prognostic significance of LGR5 expression.
authors.affiliation: Department of Gastroenterology, Aichi Cancer Center Hospital Nagoya, Japan.
authors.forename: Nobumasa
authors.initials: N
authors.lastname: Mizuno
authors.forename: Yasushi
authors.initials: Y
authors.lastname: Yatabe
authors.forename: Kazuo
authors.initials: K
authors.lastname: Hara
authors.forename: Susumu
authors.initials: S
authors.lastname: Hijioka
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Imaoka
authors.forename: Yasuhiro
authors.initials: Y
authors.lastname: Shimizu
authors.forename: Shigeru B H
authors.initials: SB
authors.lastname: Ko
authors.forename: Kenji
authors.initials: K
authors.lastname: Yamao
keywords: CD133; LGR5; cancer stem cell; endocrine cell