Molecular epidemiology of human liver cancer: insights into etiology, pathogenesis and prevention from The Gambia, West Africa

Abstract

Human liver cancer, primarily hepatocellular carcinoma (HCC), is both common and lethal. Notable variation in HCC incidence rates worldwide corresponds to the prevalence and pattern of the primary etiologic factors. In summary of decades of collaborative research centered in The Gambia, West Africa, this review explores the independent and combined effects of hepatitis B virus (HBV), hepatitis C virus (HCV) and dietary aflatoxin exposure in the etiology of HCC. Through population surveys, field trials and a series of HCC case-control studies, the patterns and natural history of HBV, HCV and aflatoxin exposures have been defined within this population. These investigations have paralleled and informed the development of molecular biomarkers of these etiologic agents and contributed to understanding the complex mechanisms involved in hepatocarcinogenesis. We discuss preventive approaches to reduce the global burden of HCC, emphasizing The Gambia Hepatitis Intervention Study, a countrywide randomized controlled trial designed to document the efficacy of HB vaccination in preventing HBV infections and HBV-related HCC. By recognizing the synergy of applying molecular techniques to population-based epidemiological studies, the portfolio of Gambian research projects presented provides a model for partnering etiologic and mechanistic investigations with applied research.