Canalicular Immunostaining of Aminopeptidase N (CD13) as a Diagnostic Marker for Hepatocellular Carcinomas

Neprilysin (CD13) is expressed in both normal and neoplastic liver tissue, where it exhibits a characteristic canalicular pattern (CD13^can) similar to the one observed with anti-CD10 antibodies and when antibodies cross-react with biliary glycoprotein I (p-CEA). The aim of this retrospective study was to investigate the use of CD13^can in differentiating between hepatocellular (HCC; 53 specimens) and non-hepatocellular carcinomas metastatic to the liver (non-HCC; 34 specimens). Immunostaining was performed with antibodies directed against CD10, CD13, p-CEA, a-fetoprotein (AFP), and HepPar1. In the HCC group, a canalicular staining pattern was found for CD13 in 48 (91%), for p-CEA in 43 (81%), and for CD10 in 30 (57%) specimens. HepPar1 was found in 29 (55%) and AFP in 17 (32%) HCCs. In the non-HCC group, CD13^can, CD10^can, and p-CEA, and immunostaining for AFP, was confined to non-neoplastic liver tissue. Two non-HCC cases showed HepPar1-immunostaining. Our results demonstrate that canalicular staining for CD13 is another highly specific marker of hepatocytic differentiation. Although it does not differentiate between benign and malignant lesions, CD13^can is clearly useful in differentiating between HCC and non-HCC.

Key words

CD13 - Differentialdiagnose - HCC