MicroRNA Expression in Focal Nodular Hyperplasia in Comparison with Cirrhosis and Hepatocellular Carcinoma

The liver disease focal nodular hyperplasia (FNH) has several histological features that resemble hepatic cirrhosis. Since cirrhosis may develop further into hepatocellular carcinoma (HCC) contrary to FNH, the aim of the present study was to identify microRNAs (miRNA), which, by their altered expression levels, may be associated with the benign, tumor-like nature of FNH. Altogether 106 surgically removed formalin-fixed paraffin-embedded liver samples were selected, including 22 FNH, 45 cirrhosis, 24 HCC and 15 normal liver tissues. Etiology of the cases of cirrhosis and HCC includes hepatitis C and alcoholism and the HCC cases developed in cirrhotic livers. Relative expression levels of 14 miRNAs were determined using TaqMan MicroRNA Assays. In comparison to normal liver, the levels of miR-34a and miR-224 were elevated not only in FNH but also in cirrhosis and HCC, while the expression of miR-17-5p, miR-18a and miR-210 was decreased in FNH. Further, the levels of miR-21 and miR-222 were increased in cirrhosis and HCC but were decreased in FNH and the expression of miR-17-5p, miR-18a, miR-195 and miR-210 was decreased in FNH as compared with cirrhosis and/or HCC. In conclusion, the elevation of miR-34a and miR-224 may be associated with both benign and malignant proliferative processes, nevertheless the increased expression of oncomiRs miR-21 and miR-222 in cirrhosis and HCC but not in FNH may be related to malignant processes of the liver. The decreased levels of miR-18a, miR-195 and miR-210 may further differentiate FNH from cirrhosis, reflecting the different pathogenesis of these two entities contrary to some histologically similar features.