Recent studies have found that hepatitis B virus Pre-S gene deletion is associated with liver disease progression; similarly, HBV variants or drug resistance are associated with an increased risk of cirrhosis and liver cancer.MarschenzS et al. found that cirrhosis progression is associated with the accumulation of complex HBV variants, manifested by enhanced viral replication, deletion of viral protein expression and abnormal localization.KalininaT also found that Pre-S gene deletion, which induces HBsAg accumulation in the endoplasmic reticulum of hepatocytes, severely impedes HBV particle secretion and is an important factor in HBV gene deletion variants leading to liver failure.Pre-S gene deletion all occurred in patients with genotype C. Pre-S2 (Pre-S2 amino acid terminus) is a high prevalence region of HBV gene deletion mutations in Beijing, and liver cancer, severe hepatitis The frequency of Pre-S2 deletion was significantly higher in patients with liver cancer, severe hepatitis and cirrhosis. Therefore, Pre-S2 gene deletion may be an important cause for the development of liver disease; however, the factors of Pre-S2 gene deletion are still not fully understood, and it is important to use antiviral drugs in a rational and scientific clinical manner.