Hepatitis B virus-associated hepatocellular carcinoma from India: role of viral genotype and mutations in CTNNB1 (beta-catenin) and TP53 genes

Purpose: Chronic hepatitis B virus (HBV) infection is the major risk factor for hepatocellular carcinoma (HCC) in India. Studies from other countries have linked HBV genotype C to a higher risk for HCC. This study was carried out to determine the association between genotype and HCC and also the frequency of mutations in CTNNB1 (beta-catenin) and TP53 genes in HBV-related HCC.
Methods: Formalin-fixed paraffin-embedded (FFPE) tissues from 20 (15 autopsy, five resected specimens) cases of HBV-associated HCC were examined. Viral genotype was determined by sequencing portions of the HBV S gene using four overlapping PCR amplicons. Exon 3 of CTNNB1 and exon 7 of TP53 were sequenced.
Results: HBV genotyping was possible in 14 of 20 cases; genotype D was most common (n = 11) followed by C (n = 2) and A (n = 1). CTNNB1 mutations were noted in two of 15 amplifiable cases while two of 10 specimens showed TP53 mutations.
Conclusions: HBV genotype can be ascertained from FFPE sections by sequencing multiple overlapping fragments to avoid the limitation of fragmented DNA. Genotype D was the common genotype in HBV-associated HCC. The very low frequency of TP53 mutation suggests low levels of aflatoxin B₁ exposure. The beta-catenin pathway appears not to be significantly involved in HBV-related HCC in India. However, further larger studies are required to confirm these findings.