Analyses of the Genetic Diversities and Mutations of the Hepatitis B Virus Genome BCP/Pre C Region.

Abstract

We wished to study the genetic diversities and mutations of the basic core promoter (BCP) and pre-C region of the hepatitis B virus (HBV) in liver-cancer tissues. One hundred and ninety-two tissue samples were collected from patients suffering from hepatocellular carcinoma (HCC) and HBV infection in 2015 in Xijing Hospital. Twenty-one cases were selected, of which direct sequencing of the polymerase chain reaction (PCR)-amplified products of BCP/pre-C region was unsuccessful. Cloning and sequencing allowed the DNA sequences of the BCP/pre-C region to be analyzed. Sequencing showed infection with mixed mutants of HBV in 37. 89% of HBV-positive HCC patients, and that HBV DNA in each sample contained 2 ~ 11 types of mutations.. The mutation rate of deletion and insertion was 80. 95%. Other mutations in descending order by mutation rate were a: A1762T/G1764A combined mutation (90. 48%); G1756C/T1803A/A(1757 ~ 1765)/A (1824 ~ 1832) combined mutation (80. 95%); T1753C/A1762T/ G1764A combined mutation (57. 14%); A1762T/G1764A/G1896A combined mutation (42. 86%); G1756C/Δ(1757~176.5) combined mutation,(28. 57%); T1753C/A1762T/G1764A/G1896A combined mutation (23. 81%). The sequencing failure of PCR products may have been correlated directly with the deletion and insertion mutations of HBV DNA. These findings lay the foundation for further studies on HBV mutations, persistent infection, and the mechanism of personalized medicine.