Abstract 3630: Comprehensive integrated HBV DNA profiling in HCC patients with GGH by HBV-targeted NGS andPacBio sequencinganalysis

Despite current antiviral therapy success in reducing viral load in patients with chronic hepatitis B virus (HBV), persistent viral surface antigen (HBsAg) remains a risk factor of HCC. Recent evidence has shown that integrated HBV can serve as a source for continued viral antigen expression, despite the lack of detectable replication. Given the oncogenicity of pre-S mutant proteins and its expression in type II ground glass hepatocytes (GGH) even in the absence of viral replication, we assessed the likelihood of GGH as a pre-malignant state as compared to other adjacent-to-tumor non-GGH “normal” tissue by investigating the integrity of integrated HBV DNA. We developed a sensitive HBV-targeted NGS and downstream bioinformatics pipeline, ChimericSeq, to identify HBV-host junctions. A pilot study of 10 HBV-HCC patients, each with six micro-dissected FFPE tissue sections (2 tumor, 2 GGH, 2 HBsAg-negative), was subjected to HBV-targeted NGS and ChimericSeq analysis. We identified integrated HBV DNA in 90% of HCC as well as its matched GGH, and identified PreS2 deletions, for instance, deletion at nt. 43-52. Surprisingly, the recurrent insertional driver mutations of TERT, CCNE1, and ABCC13 integration were detected in 9 of 10 (90%) of this GGH/HCC patient cohort. Next we performed PacBio amplicon sequencing of integrated HBV DNA including Pre-S sequences to comprehensively profile the integrity of the integrated HBV DNA, such as insertional mutations or deletion, and mutations across the different frozen tissue sections (tumor, GGH, HBsAg-negative). Our data suggest that HBV integration of cancer driver genes occurs early during course of infection and integrated DNA evolved over time during carcinogenesis. Overall, a sensitive workflow to comprehensively profile integrated HBV DNA in HCC patients enables further investigation of the role of HBV integration during tumorigenesis. Citation Format: Yu-Lan Kao, Yih-Ping Su, Hung-Wen Tsai, Ih-Jen Su, Selena Lin, Wei Song, Ying-Hsiu Su. Comprehensive integrated HBV DNA profiling in HCC patients with GGH by HBV-targeted NGS and PacBio sequencing analysis [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 3630.