Unraveling the role of hepatitis B virus DNA integration in B-cell lymphomagenesis

Studies have shown that hepatitis B virus (HBV)-associated B-cell non-Hodgkin lymphoma (NHL) constitutes a unique subgroup with distinct clinical features. It still leaves open the question of whether the integration of HBV DNA into the B-cell genome is a causal mechanism in the development of lymphoma. Using the hybridisation capture-based next generation sequencing and RNA sequencing, we characterised the HBV integration pattern in 45 HBV-associated B-cell NHL tumour tissues. A total of 354 HBV integration sites were identified in 13 (28.9%) samples, indicating the relatively low integration frequency in B-cell NHLs. High plasma HBV DNA loads were not associated with the existence of HBV integration. The insertion sites distributed randomly across all the lymphoma genome without any preferential hotspot neither at the chromosomal level nor at the genetic level. Intriguingly, most HBV integrations were nonclonal in B-cell NHLs, implying that they did not confer a survival advantage. Analysis of the paired diagnosis-relapse samples showed the unstable status of HBV integrations during disease progression. Furthermore, transcriptomic analysis revealed the limited biological impact of HBV integration. Our study provides an unbiased HBV integration map in B-cell NHLs, revealing the insignificant role of HBV DNA integration in B-cell lymphomagenesis.