Background & aims: The hepatitis B virus (HBV) genome encodes specific sequence elements which promote splicing of viral DNA. It has been previously suggested that spliced HBV (spHBV) variants promote viral replication and protein production, leading to hepatocellular carcinoma (HCC). In this study, we have analysed changes in spHBV over time; providing the first longitudinal analysis of spHBV in relation to the development of HCC.
Methods: Serial serum samples were collected from 165 patients with chronic HBV monoinfection, including 58 patients who later developed HCC. Real-time PCR was used to amplify and quantify wt and sp DNA loads.
Results: spHBV was detected in over 80% of patients with chronic HBV infection. Median serum spHBV levels were significantly higher in HCC patients than HCC-free control patients (p<0.001). Univariate analysis revealed a strong correlation between time to HCC diagnosis and spHBV DNA levels (τ=0.203; p=0.016). Asian HBV genotype (p=0.025) and increased viral load (p<0.001) were also significantly associated with increased spHBV DNA levels. Multiple regression analysis revealed time to diagnosis of HCC, Asian HBV genotypes, and viral load to be associated with increased spHBV DNA (model p<0.001; R(2)=0.189).
Conclusions: HBV splicing is a common event during chronic infection and increases prior to diagnosis of HCC. Measurement of HBV splicing may prove a valuable adjunct to be used in the identification of chronically infected patients who are at increased risk of developing HCC.
Keywords: Chronic infection; Hepatitis B virus (HBV); Hepatocellular carcinoma (HCC); Liver transplantation; Real-time PCR; Viral splicing.
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