Analysis of HBV genotypes and nucleoside drug-resistance mutations in tumor patients with HBV infection

Objective: To analyze the distribution characteristics of HBV genotypes and polymerase/reverse transcriptase(RT) region-related drug-resistant mutations in tumor patients with HBV infection,and provide evidences for prevention of HBV reactivation and antiviral therapy in clinical tumor patients. Methods: A total of 130 HBV infection tumor patients with positive viral DNA load were selected.HBV gene typing was performed by PCR-RFLP method,and then nested PCR method was used to amplify RT region genes.The PCR products were sequenced by Sanger method to analyze the mutation sites and drug resistance of RT region gene sequence. Results: Among the 130 tumor patients,16 cases of HBV were type B(12.31%),100 cases were type C (76.92%),and 14 cases were type B+C(10.77%).The drug resistance rate of HBV was 26.15%,including 30.00% for C type,14.29% for B+C type and 12.50% for B type,and there was no statistical significance in the drug resistance rate among three genotypes(P>0.05).A total of 11 types of drug-resistant mutations and 3 mutation modes in RT region sequencing were detected,and the mutation rate of 180,181 and 204 sites were higher.Lamivudine resistance rate was the highest (70.59%),Entecavir resistance rate was the lowest (5.88%),and the type C was the main type.In addition,the associated rtV173L+rtL180M+rtM204V triple mutant with E164D+I195M in RT region was not detected. Conclusions: The genotype of HBV infection tumor patients is mainly type C,and the drug resistance rate is 26.15%.The drug resistance mutation rate,mutation pattern complexity and drug resistance types of different genotypes were the highest in genotype C,and no corresponding HBsAg immune escape mutation in RT region is found.It is recommended that tumor patients use nucleoside analogues with high resistance barrier to prevent HBV reactivation.