Association of HCV-NS5B protein persistence and viral load in the development of Hepatocellular Carcinoma in resected liver tissues of HCV associated HCC patients

Abstract

Hepatocellular Carcinoma (HCC) is the most frequently occurring of all types of cancers that originate from the liver. HCC is one of the top four mortality related cancers that accounts for approximately 800,000 deaths annually. Viral hepatitis is the most common of all the factors involved in HCC development. Hepatitis B Virus (HBV) and Hepatitis C Virus (HCV) account for approximately 80% of all the HCCs, with 50%-80% being HBV and 10%-25% being HCV induced of all the viral associated HCC cases, worldwide. Hepatitis C Virus (HCV) is the most prevalent, among all the hepatitis viruses, in Pakistan. 6% of Pakistani population i.e., approximately 10 million people are affected by HCV. Pakistan contributes to high burden of HCV, worldwide and ranks second with highly prevalent HCV, after Egypt. Increasing incidence of HCV has increased the HCV associated HCC rates in Pakistan. Lack of early and efficient diagnosis of and effective treatment against HCV infections are contributing factors for increased HCV-HCC rates, in Pakistan. Currently used post-treatment follow up method by physicians for treated HCV patients is the quantification of detectable HCV-RNA in their serums. Undetectable serum HCV-RNA does not reflect the completely eliminated risk of HCV and virus may still be present as a persistent infection in hepatocytes (liver tissues) of affected individuals. Thus, post-treatment follow-up by serum/blood quantification alone cannot give valid results with neglected possibility of persistent liver infection. This makes quantification of viral load in liver tissues important, as a post-treatment follow-up strategy. Abstract xx In the present study, quantification of viral load was performed in liver tissues of treated HCV-HCC patients via quantitative Real Time PCR. Some samples had detectable HCV-RNA (44%) while most samples had undetectable HCV-RNA (56%) in their liver tissues. A semi-quantitative analysis of HCV-NS5B expression was performed via Immunohistochemical (IHC) staining using anti-NS5B primary antibody. Semi-quantitative analysis of NS5B showed persistent NS5B expression in liver tissues of all HCV-HCC patients, irrespective of the detectable or undetectable HCV-RNA in their liver tissues, with most (i.e., 81%) of the liver tissues having Low (01), while others having Moderate (02) (6%) and High (03) (13%) IHC scores. Findings of the present study, which show presence of persistent infection in form of detectable viral loads in some and NS5B expression in all the liver tissues of HCV HCC patients, hint at the dire need of effective therapeutic treatment strategies to not only reduce the blood viral loads in treated patients but also target the persistent infection in hepatocytes of HCV affected individuals. Also, improved post-treatment follow up strategies are required, other than those generally used by the physicians in which only the blood/serum is quantified for undetectable HCV-RNA and is anticipated that an individual has recovered from the virus, when persistent viral load in hepatocytes can be of great potential health threat resulting in occurrence or recurrence of HCC.