Utility of mir-21 Detection by Rapid Chromogenic in situ Hybridization (CISH) in the Diagnosis of Well and Moderately Differentiated (WD) Hepatocellular Carcinoma (HCC)

Abstract

An estimated 70% to 80% of all HCCs arise from cirrhotic liver, especially postchronic HBV or HCV infection. Identifying WD HCC arising in the background of cirrhosis is challenging on morphology in core biopsies. In addition, presence of dysplasia (micro/macro) in cirrhotic nodules makes the task more difficult. In HCC, miRNAs have aberrant expression profiles, with possible applications in diagnosis, especially for early, presymptomatic disease, and prognosis of HCC. Multiple studies have consistently demonstrated that along with other mi-RNAs, there is increased expression of mir-21 in HCC. Similar studies have shown mir-21 simultaneously regulates multiple programs that enhance cell proliferation, apoptosis, or tumor invasiveness in HCC. Methods of subcellular and tissue localization of mi-RNAs are essential to understand their biological roles and their contribution to disease along with diagnosis. The aim of this study is to evaluate the utility of mir-21 detection by CISH as a diagnostic tool in the setting of well and moderately differentiated (MD) HCCs. Archival blocks were retrieved and slides were reviewed with clinical information on 8 HCC and 5 normal liver resections. In 8 HCC, 5 cases were HBV and HCV infected with cirrhosis. Manufacturer's guidelines were followed for CISH (NAR-I, FAM-labeled Hsa-miR-21 probe, BioGenex). Nuclear mir-21 CISH stain was graded as: negative (-), weak (1+), moderate (2+) or strong (3+) and distribution was focal (50%). Neoplastic cells in HCC showed strong (2-3) multifocal to diffuse nuclear staining for miR-21 in 8/8 (100%) compared with the staining seen in normal liver cells. Currently other than morphology on H&E, there are no definite helpful immunohistochemical markers aiding in differentiating dysplasia (micro/macro) vs WD HCC on a core biopsy in a postinfectious cirrhotic liver. Here we offer a rapid CISH technique which can clearly identify increased nuclear expression of mir-21.