Quasispecies variant of pre-S/S gene in HBV-related hepatocellular carcinoma with HBs antigen positive and occult infection

Yuri Hatazawa; Yoshihiko Yano; Rina Okada; Toshihito Tanahashi; Hiroki Hayashi; Hirotaka Hirano; Akihiro Minami; Yuki Kawano; Motofumi Tanaka; Takumi Fukumoto; Yoshiki Murakami; Masaru Yoshida; Yoshitake Hayashi

doi:10.1186/s13027-018-0179-4

Quasispecies variant of pre-S/S gene in HBV-related hepatocellular carcinoma with HBs antigen positive and occult infection

Infect Agent Cancer. 2018 Feb 2:13:7. doi: 10.1186/s13027-018-0179-4. eCollection 2018.

Authors

Affiliations

¹ 1Division of Gastroenterology, Department of Internal Medicine, Kobe University Graduate School of Medicine, Kobe, Hyogo 650-0017 Japan.
² 2Division of Molecular Medicine & Medical Genetics, Department of Pathology, Kobe University Graduate School of Medicine, Kobe, Japan.
³ Department of Internal Medicine, Tokushima Prefectural Naruto Hospital, Tokushima, Japan.
⁴ 4Division of Hepato-Biliary-Pancreatic Surgery, Department of Surgery, Kobe University Graduate School of Medicine, Kobe, Japan.
⁵ 5Department of Hepatology, Osaka City University Graduate School of Medicine, Osaka, Japan.

Abstract

Background: Hepatocellular carcinoma (HCC) can develop in patients who are negative for the hepatitis B surface antigen (HBsAg) in serum but positive for hepatitis B virus (HBV) DNA in the liver, referred to as occult HBV infection (OBI). Previous reports showed that HBV variants in OBI-related HCC are different from those in HBsAg-positive HCC. In the present study, HBV quasispecies based on the pre-S/S gene in OBI-related HCC patients were examined by high throughput sequencing and compared with those in HBsAg-positive HCC.

Methods: Nineteen tissue samples (9 OBI-related and 10 HBsAg-positive non-cancerous tissues) were collected at the time of surgery at Kobe University Hospital. The quasispecies with more than 1% variation in the pre-S/S region were isolated and analysed by ultra-deep sequencing.

Results: There were no significant differences in the major HBV populations, which exhibit more than 20% variation within the entire pre-S/S region, between OBI-related HCC and HBsAg-positive HCC. However, the prevalences of major populations with pre-S2 region mutations and of minor populations with polymerized human serum albumin-binding domain mutations were significantly higher in OBI-related HCC than in HBsAg-positive HCC. Moreover, the major variant populations associated with the B-cell epitope, located within the pre-S1 region, and the a determinant domain, located in the S region, were detected frequently in HBsAg-positive HCC. The minor populations of variants harbouring the W4R, L30S, Q118R/Stop, N123D and S124F/P mutations in the pre-S region and the L21F/S and L42F/S mutations in the S region were detected more frequently in OBI-related HCC than in HBsAg-positive HCC.

Conclusions: Ultra-deep sequencing revealed that the B-cell epitope domain in the pre-S1 region and alpha determinant domain in the S region were variable in HBsAg-positive HCC, although the quasispecies associated with the pre-S2 region were highly prevalent in OBI-related HCC.

Trial registration: Ref: R000034382/UMIN000030113; Retrospectively registered 25 November 2017.

Keywords: HBV; HCC; Occult; Pre-S/S; Quasispecies; Ultra-deep sequencing.