title: Absence of L1 in pancreatic masses distinguishes adenocarcinomas from poorly differentiated neuroendocrine carcinomas.
abstract: BACKGROUND
  Pancreatic adenocarcinoma is a tumor with fatal outcome. Cell adhesion molecules, such as L1 (CD171), have an essential function in tumor progression. L1 has been shown to be specifically expressed in poorly differentiated neuroendocrine carcinomas of the pancreas. The aim of this study was to determine the expression of L1 in pancreatic adenocarcinomas to evaluate whether L1 might differentiate between pancreatic carcinomas of neuroendocrine and ductal origin.
  
  
  METHODS
  L1 expression was retrospectively analyzed in 111 cases of pancreatic adenocarcinomas by immunohistochemistry on paraffin sections of primary tumors. Staining was performed by the peroxidase technique with monoclonal antibody against human L1. All tumors were classified according to the most recent TNM classification.
  
  
  RESULTS
  The focal expression of L1 was detected in 2 (2%) out of 111 pancreatic carcinomas only, the remaining 109 (98%) being L1-negative. No expression was found in acinar or ductal cells of normal pancreatic tissue.
  
  
  CONCLUSIONS
  Our data suggest that L1 is expressed in few cases of pancreatic ductal adenocarcinoma. Since L1 was previously found to be expressed specifically in neuroendocrine pancreatic carcinomas, its absence in unclear pancreatic masses might hint at a ductal origin for a malignant pancreatic tumor.
authors.affiliation: Department of General, Visceral and Thoracic Surgery, University Medical Center Hamburg-Eppendorf, 20246 Hamburg, Germany. jkaifi@uke.uni-hamburg.de
authors.forename: Jussuf T
authors.initials: JT
authors.lastname: Kaifi
authors.forename: Sina
authors.initials: S
authors.lastname: Heidtmann
authors.forename: Paulus G
authors.initials: PG
authors.lastname: Schurr
authors.forename: Uta
authors.initials: U
authors.lastname: Reichelt
authors.forename: Oliver
authors.initials: O
authors.lastname: Mann
authors.forename: Emre F
authors.initials: EF
authors.lastname: Yekebas
authors.forename: Robin
authors.initials: R
authors.lastname: Wachowiak
authors.forename: Tim
authors.initials: T
authors.lastname: Strate
authors.forename: Melitta
authors.initials: M
authors.lastname: Schachner
authors.forename: Jakob R
authors.initials: JR
authors.lastname: Izbicki
mesh_terms: D000230:Adenocarcinoma / Q000276:immunology* / Q000473:pathology*; D018278:Carcinoma, Neuroendocrine / Q000276:immunology* / Q000473:pathology*; D005260:Female; D006801:Humans; D039841:Leukocyte L1 Antigen Complex / Q000096:biosynthesis*; D008297:Male; D008875:Middle Aged; D009367:Neoplasm Staging; D010190:Pancreatic Neoplasms / Q000276:immunology* / Q000473:pathology*
chemical_list: D039841:Leukocyte L1 Antigen Complex