1) Determine the prevalence and viral genetic variability, including HBV genotypes and mutations, in patients co-infected with HBV/HCV
2) Determine the prevalence and viral genetic variability, including genotypes and mutations, of occult HBV infection in patients with HBsAg/anti-HCV-negative chronic liver disease
3) Quantify intrahepatic cccDNA in patients with occult or overt HBV infections of various stages of disease, including chronic hepatitis, cirrhosis and HCC
4) Determine the association between chronic HBV infection and CCA by specifically demonstrating cccDNA in liver tumor tissue