Evolution of Non-alcoholic Fatty Liver Disease to Liver Cancer: Insights from Genome-wide Association Studies

Abstract

Non-alcoholic fatty liver disease (NAFLD) is the most prevalent liver disease, affecting a quarter of the world’s population. The spectrum of NAFLD ranges from simple steatosis, non-alcoholic steatohepatitis (NASH), fibrosis, cirrhosis, and ultimately to hepatocellular carcinoma (HCC). Multiple factors are involved in the pathogenesis and progression of NAFLD, wherein genetic, epigenetic, environmental, gut-microbiome, and dietary factors play a substantial role. Robust genome-wide association studies (GWAS) have recently identified several genetic alterations contributing to NAFLD progression to liver cancer. This review describes the most critical genetic variations identified in various genes that modulate NAFLD pathogenesis. As expected, NAFLD shows gene variations that regulate or influence hepatocyte lipid metabolism. In addition to polymorphisms in genes that regulate insulin signaling, fibrosis, inflammation, and oxidative stress, cytokine/chemokine-expressing genes also participate in NAFLD pathogenesis. GWAS helped us distinguish genetic polymorphisms that modulate steatosis, fibrosis, or both in NAFLD patients. Identifying genetic factors predisposing an individual to NAFLD helps stratify people at high risk and aids in imparting preventive strategies early in life. Such studies should also help in adopting prevention strategies and targeted treatment regimes.