Arginase-1, HepPar-1, and Glypican-3 are the most effective panel of markers in distinguishing hepatocellular carcinoma from metastatic tumor on fine-needle aspiration specimens.

Distinction of liver metastases from hepatocellular carcinoma (HCC) may present a diagnostic challenge. Arginase-1 (Arg-1) is a marker for HCC recently described in some literature. Immunohistochemical evaluation of Arg-1, hepatocyte paraffin-1 (HepPar-1), and glypican-3 expression was performed on 1,240 surgical specimens and 62 liver fine-needle aspiration specimens (29 HCCs, 28 metastatic tumors, and 5 benign liver cases). The staining results on tissue microarray sections showed that 2.7% and 3.1% of nonhepatic tumor cases were positive for HepPar-1 and glypican-3, respectively; none was positive for Arg-1. For fine-needle aspiration specimens, 19 HCCs were positive for all 3 markers; 9 were positive for 1 or 2 markers; and only 1 case was negative for all 3 markers. These data demonstrate that Arg-1 is the most specific marker in differentiating a non-HCC from HCC. It is recommended to use 3 markers as a panel in distinguishing HCC from metastatic carcinoma.