HEPA

(Hepatocyte antigen)
Assessments
Characteristics
Mitochondrial membrane protein of unknown function almost exclusively occurring in liver cells, detected immunohistochemically with the mAb Hepatocyte Paraffin 1 (Hep Par 1, Clone: OCH1E5 or OCH1E5.2.10). The protein is also found in enterocytes (often focally) in small bowel mucosa.
Neoplasms
The majority (70-90%) of primary hepatocellular carcinomas (HCC) are positive, sometimes only focally. Adenocarcinomas in the gastrointestinal (GI) tract has shown focal positivity in up to 50%. Also adenocarcinomas derived from pancreas, lung and ovary have occasionally shown positivity. Rare hepatoid adenocarcinomas of GI tract and other organs as well as hepatoid yolk sac tumour are positive.
Application
Hepa is useful for the differential diagnosis of hepatocellular tumors in general, for the differentiation of clear cell HCC from other clear cell malignancies, and for the distinction of hepatoblastoma, especially the embryonal type, from other small, round-cell tumors of childhood. However, Hepa should be used in a panel, which in case of the differential diagnosis HCC should include, e.g., AFP, CD10, CD66a, CK7, CK20, and Glypican 3.
Controls
Liver can be used as positive control, in which virtually all liver cells must show an at least moderate granular cytoplasmic staining reaction. Tonsil can be used as negative control – no staining should be seen.
Selected references
Fasano M, Theise ND, Nalesnik M, Goswami S, Garcia de Davila MT, Finegold MJ, Greco MA. Immunohistochemical evaluation of hepatoblastomas with use of the hepatocyte-specific marker, hepatocyte paraffin 1, and the polyclonal anti-carcinoembryonic antigen. Mod Pathol. 1998 Oct;11(10):934-8. PubMed PMID: 9796718. Lamps LW, Folpe AL. The diagnostic value of hepatocyte paraffin antibody 1 in differentiating hepatocellular neoplasms from nonhepatic tumors: a review. Adv Anat Pathol. 2003 Jan;10(1):39-43. Review. PubMed PMID: 12502967. Maitra A, Murakata LA, Albores-Saavedra J. Immunoreactivity for hepatocyte paraffin 1 antibody in hepatoid adenocarcinomas of the gastrointestinal tract. Am J Clin Pathol. 2001 May;115(5):689-94. PubMed PMID: 11345832. Minervini MI, Demetris AJ, Lee RG, Carr BI, Madariaga J, Nalesnik MA. Utilization of hepatocyte-specific antibody in the immunocytochemical evaluation of liver tumors. Mod Pathol. 1997 Jul;10(7):686-92. PubMed PMID: 9237179. Murakata LA, Ishak KG, Nzeako UC. Clear cell carcinoma of the liver: a comparative immunohistochemical study with renal clear cell carcinoma. Mod Pathol. 2000 Aug;13(8):874-81. PubMed PMID: 10955454. Wennerberg AE, Nalesnik MA, Coleman WB. Hepatocyte paraffin 1: a monoclonal antibody that reacts with hepatocytes and can be used for differential diagnosis of hepatic tumors. Am J Pathol. 1993 Oct;143(4):1050-4. PubMed PMID: 7692729; PubMed Central PMCID: PMC1887067.
06.12.12 - MV/LE