title: Myofibroblasts are responsible for the desmoplastic reaction surrounding human pancreatic carcinomas.
abstract: BACKGROUND
  The cell type responsible for the desmoplastic reaction surrounding human pancreatic carcinoma is unknown. Hepatic stellate cells, which activate to a myofibroblast-like form, are responsible for collagen deposition in cirrhosis and around hepatocellular carcinomas. Recently, pancreatic stellate cells have been described and implicated in the fibrosis of chronic pancreatitis. We sought to determine whether these cells are responsible for the scirrhous reaction surrounding pancreatic adenocarcinomas.
  
  
  METHODS
  Archival formalin-fixed, paraffin-embedded pancreatic tissues from 10 patients undergoing pancreaticoduodenectomy for ductal adenocarcinoma and from 2 patients with pancreatic islet cell tumors were examined immunohistochemically for alpha-smooth muscle actin (alpha-SMA), smooth muscle myosin heavy chain (SMMHC), procollagen I, collagen IV, and endothelial cell markers, von Willebrand factor and cluster of differentiation 31.
  
  
  RESULTS
  In non-neoplastic areas, staining for alpha-SMA and SMMHC was confined to interlobular septal regions. In contrast, the desmoplastic reaction surrounding all 10 pancreatic adenocarcinoma specimens displayed intense interstitial staining for alpha-SMA, SMMHC, and collagen IV but no staining for von Willebrand factor and cluster of differentiation 31. Procollagen I staining localized intracellularly to fibroblast-shaped cells within this alpha-SMA/SMMHC-positive scirrhous region. Islet cell tumors demonstrated an increase in alpha-SMA staining, although this was not as marked as in ductal adenocarcinomas.
  
  
  CONCLUSIONS
  A massive increase in myofibroblast activity, compatible with the activation of stellate cells, is associated with the deposition of collagen types I and IV in the desmoplastic reaction around pancreatic adenocarcinomas.
authors.affiliation: Department of Surgery, University of Washington School of Medicine, Seattle, USA.
authors.forename: Tina W f
authors.initials: TW
authors.lastname: Yen
authors.forename: Nils Petter
authors.initials: NP
authors.lastname: Aardal
authors.forename: Mary P
authors.initials: MP
authors.lastname: Bronner
authors.forename: David R
authors.initials: DR
authors.lastname: Thorning
authors.forename: Christopher E
authors.initials: CE
authors.lastname: Savard
authors.forename: Sum P
authors.initials: SP
authors.lastname: Lee
authors.forename: Richard H
authors.initials: RH
authors.lastname: Bell
mesh_terms: D000199:Actins / Q000032:analysis; D000368:Aged; D024141:Collagen Type IV / Q000032:analysis; D005260:Female; D005347:Fibroblasts / Q000473:pathology; D006801:Humans; D007150:Immunohistochemistry; D008297:Male; D008875:Middle Aged; D018994:Myosin Light Chains / Q000032:analysis; D010190:Pancreatic Neoplasms / Q000737:chemistry / Q000473:pathology*; D016212:Transforming Growth Factor beta / Q000502:physiology
chemical_list: D000199:Actins; D024141:Collagen Type IV; D018994:Myosin Light Chains; D016212:Transforming Growth Factor beta