ORIGINAL ARTICLE: Diagnostic immunomarkers for HepPar-1 negative areas of hepatocellular carcinoma

Background and aim: HepPar-1 is a sensitive and specific antibody. However, when used for the diagnosis of hepatocellular carcinoma (HCC), especially in needle biopsy specimens, this diagnostic approach is limited by potential multifocal expression and/or poorly differentiated HCCs, where it may not be expressed. The goal of this study was to determine the antibodies most sensitive to hepatocyte differentiation in HepPar-1 negative areas including: CD13, CD10, polyclonal carcinoembryonic antigen (pCEA), alpha-fetoprotein (AFP) and glypican-3, for needle biopsy. Methods: Fifty cases of HCCs were obtained from surgically resected livers. Immunohistochemical staining for hepatocyte and biliary markers- HepPar-1, CD13, glypican-3, pCEA, CD10, AFP, cytokeratin (CK)7, CK19, and epithelial cell adhesion molecule (EpCAM) was performed from paraffin block samples. Results: HepPar-1 was diffusely negative in 12 cases. Twenty two cases showed partial expression of the HepPar-1 antibody. Among 34 HepPar-1 negative areas, CD13 was the most consistent antibody (85.3%, 29/34) showing the characteristic bile canaliculi pattern. Immunoexpression of biliary differentiation with CK7, CK19, and EpCAM showed no significant differences in HepPar-1 negative areas. Conclusions: CD13 could be used for the detection of hepatocyte differentiation in HCCs with HepPar-1 negative expression, especially in needle biopsy specimens. In addition, negative immunoexpression for HepPar-1 was not overtly related to biliary differentiation, from an immunohistochemical viewpoint.