Phylogenetic Analysis of HBV Based on PreS Region in Iranian Hepatocellular Carcinoma Patients

There are eight genotypes (A-H) of hepatitis B virus (HBV), which show a characteristic worldwide distribution. Genotyping can be accomplished based on a partial sequence of HBV genome such as the PreS or S gene. The aim of this study was to determine the HBV genotypes in Iranian hepatocellular carcinoma (HCC) patients with chronic HBV infection. Serum sample of 10 HCC patients with chronic HBV infection were subjected to PreS Hemi-Nested PCR. The viral genotype of each sample was determined by bi-directional sequencing of the PreS amplicon and phylogenetic analysis by comparing the nucleotide sequence with 33 reference HBV strains obtained from the GenBank. Phylogenetic analysis based on PreS region sequences disclosed that all isolated strains belonged to genotype D. Analysis of sequences revealed that all the sequences contained amino acid substitutions. In the PreS2 region of two samples, a point mutation in the start codon was found. There were some deletions with 3, 6 and 8 amino acids in PreS2 region of three samples. Despite the low number of samples, these data revealed that the HBV genotype D is dominant in Iranian HCC patients. Most of the mutations are located at immunodominant epitopes involved in B or/and T cell recognition.