Human pathology
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Comparative Study
Diagnostic significance of aquaporin-1 in liver tumors.
The diagnostic utility of aquaporin (AQP)-1 in liver tumors was tested and compared with other well-established markers. In 30 cholangiocarcinomas (CCs), 20 hepatocellular carcinomas (HCCs), and 10 metastatic colorectal carcinomas (MCCs) of the liver, expression of AQP-1, CD10, cytokeratin (CK) 7, CK20, and polyclonal carcinoembryonic antigen (pCEA) was tested. In addition, staining patterns of CD10 and pCEA were analyzed. ⋯ Canalicular staining patterns of CD10 and pCEA were observed in HCC (100% and 89.5%, respectively) but typically not in CC (0% and 6.7%, respectively) and never in MCC. In cholestatic disease, AQP-1 was expressed in differentiated epithelial cells of the bile ducts, whereas CK7-positive hepatocytes of Rappaport zone 1 did not show any AQP-1 reactivity. Therefore, AQP-1 seems to be a highly selective marker for differentiated cholangiocytes and can be very helpful in the differential diagnosis of liver tumors.