title: Immunoreactivity for hepatocyte paraffin 1 antibody in hepatoid adenocarcinomas of the gastrointestinal tract.
abstract: Hepatocyte paraffin 1 (Hep Par 1) is a monoclonal antibody considered almost specific for normal and neoplastic hepatocytes, that can be used on formalin-fixed paraffin-embedded tissues. Hep Par 1 reactivity has been demonstrated consistently in hepatocellular carcinomas and hepatoblastomas but only rarely in cholangiocarcinomas and metastatic tumors to the liver. Although its role as a marker of hepatocytic differentiation in primary liver tumors has been studied extensively, Hep Par 1 expression has not been explored in extrahepatic lesions, especially rare adenocarcinomas with hepatoid morphologic features. We studied 7 hepatoid adenocarcinomas of the gastrointestinal tract (6 gastric and 1 from the gallbladder) for Hep Par 1 immunoreactivity. Focal Hep Par 1 expression was seen in 6 of 7 tumors. These hepatoid adenocarcinomas also showed reactivity for alpha-fetoprotein and carcinoembryonic antigen. The presence of Hep Par 1 reactivity in extrahepatic hepatoid adenocarcinomas underscores the fact that Hep Par 1 expression is not unique to primary hepatocellular neoplasms. Adenocarcinomas with hepatoid features must be considered in the differential diagnosis of Hep Par 1-positive lesions.
authors.affiliation: Division of Anatomic Pathology, University of Texas Southwestern Medical Center, 5323 Harry Hines Blvd, Dallas, TX 75235, USA.
authors.forename: A
authors.initials: A
authors.lastname: Maitra
authors.forename: L A
authors.initials: LA
authors.lastname: Murakata
authors.forename: J
authors.initials: J
authors.lastname: Albores-Saavedra
mesh_terms: D000230:Adenocarcinoma / Q000276:immunology* / Q000473:pathology; D000368:Aged; D000911:Antibodies, Monoclonal / Q000276:immunology*; D014408:Biomarkers, Tumor / Q000276:immunology; D002272:Carcinoembryonic Antigen / Q000276:immunology; D003429:Cross Reactions; D005260:Female; D005706:Gallbladder Neoplasms / Q000276:immunology* / Q000473:pathology; D022781:Hepatocytes / Q000276:immunology*; D006801:Humans; D007150:Immunohistochemistry; D008297:Male; D008875:Middle Aged; D013274:Stomach Neoplasms / Q000276:immunology* / Q000473:pathology; D000509:alpha-Fetoproteins / Q000276:immunology
chemical_list: D000911:Antibodies, Monoclonal; D014408:Biomarkers, Tumor; D002272:Carcinoembryonic Antigen; D000509:alpha-Fetoproteins