1. Host factors (1) age >50 years; (2) male; (3) cirrhosis; (4) family history of hepatocellular carcinoma; (5) African or Asian race; (6) obesity; (7) diabetes mellitus. 2, viral factors (1) high replication level of HBV; (2) genotype (C>B); (3) BCP region variation. 3, environmental factors (1) HCV or HDV co-infection; (2) alcohol; (3) aflatoxin.