Liquid Biopsy as a Non-invasive Tool for the Diagnosis of NASH and Liver Fibrosis

Nonalcoholic fatty liver disease (NAFLD) has evolved to represent the most common cause of chronic liver disease globally. Today, NAFLD is a leading indication for liver transplantation and a major etiology for hepatocellular carcinoma (HCC) in the United States. NAFLD is characterized by the excess accumulation of lipids within the liver and ranges from isolated steatosis to nonalcoholic steatohepatitis (NASH), which is characterized by the presence of hepatic necroinflammation, hepatocyte ballooning and fibrosis progression.

Currently, liver biopsy remains the gold standard for the diagnosis of various chronic liver diseases, and for determining the severity of liver injury, inflammation, and fibrosis stage. However, this procedure is invasive, prone to complications such as bleeding and is associated with sampling variability and limited representation of the whole liver. Other limitations include, the difficulty to monitor liver injury progression over time and underestimation of disease severity.

Despite intensive research, currently available non-invasive blood tests are not sufficiently sensitive or specific and are therefore of limited use. Blood biomarkers might provide significant advances in the diagnosis and monitoring of disease progression and regression in clinical settings.

Recently, liquid biopsy has emerged as a potential, less invasive, alternative to liver biopsy. In fact, it addresses several unmet clinical needs, including sensitivity, specificity, the determination of prognoses, and the prediction of therapeutic responses.