title: Arginase-1: a highly specific marker separating pancreatic adenocarcinoma from hepatocellular carcinoma.
abstract: BACKGROUND
  Arginase-1 and HepPar-1 are effective immunohistochemical (IHC) markers for hepatocellular carcinoma (HCC). In this study, we explored the possible efficacy of these stains in diagnosing pancreatic adenocarcinoma (PAD).
  
  
  METHODS
  Arginase-1 and HepPar-1 IHC was performed on formalin-fixed, paraffin-embedded fine needle aspiration (FNA) cell blocks (CB) of PAD (n = 46), tissue microarray (TMA) of PAD (n = 33), FNA CB of HCC (n = 44) and TMA of HCC (n = 85). Negative controls without carcinoma were also applied (pancreas CB, n = 7; pancreas TMA, n = 3).
  
  
  RESULTS
  PAD CB demonstrated arginase-1 positivity in 0 of 46 cases and HepPar-1 positivity in 7 of 46 cases (15%). PAD TMA demonstrated arginase-1 positivity in 0 of 33 cases and HepPar-1 positivity in 4 of 33 cases (12%). HCC CB demonstrated arginase-1 positivity in 37 of 44 cases (84%) and HepPar-1 positivity in 32 of 44 cases (72%). HCC TMA demonstrated arginase-1 positivity in 75 of 85 cases (88%) and HepPar-1 positivity in 80 of 85 cases (94%).
  
  
  CONCLUSIONS
  Both arginase-1 and HepPar-1 are effective IHC markers of hepatocellular differentiation. Arginase-1 demonstrates superior sensitivity and specificity compared with HepPar-1 in the diagnosis of HCC. However, both arginase-1 and HepPar-1 have a low sensitivity and a very high specificity for PAD.
authors.affiliation: Department of Pathology and Laboratory Medicine, Emory University Hospital, Atlanta, Ga., USA.
authors.forename: Nazneen
authors.initials: N
authors.lastname: Fatima
authors.forename: Cynthia
authors.initials: C
authors.lastname: Cohen
authors.forename: Momin T
authors.initials: MT
authors.lastname: Siddiqui
mesh_terms: D000230:Adenocarcinoma / Q000175:diagnosis* / Q000201:enzymology; D001119:Arginase / Q000032:analysis / Q000096:biosynthesis*; D014408:Biomarkers, Tumor / Q000032:analysis / Q000378:metabolism*; D006528:Carcinoma, Hepatocellular / Q000175:diagnosis* / Q000201:enzymology; D006801:Humans; D007150:Immunohistochemistry; D008113:Liver Neoplasms / Q000175:diagnosis* / Q000201:enzymology; D010190:Pancreatic Neoplasms / Q000175:diagnosis* / Q000201:enzymology; D046888:Tissue Array Analysis
chemical_list: D014408:Biomarkers, Tumor; C574619:ARG1 protein, human; D001119:Arginase