Mutations within the hepatitis B virus genome among chronic hepatitis B patients with hepatocellular carcinoma

HBV preS Mutations Promote Hepatocarcinogenesis by Inducing Endoplasmic Reticulum Stress and Upregulating Inflammatory Signaling

Simple Summary

Viral mutations at the preS region of hepatitis B virus (HBV) significantly increase the risk of developing hepatocellular carcinoma (HCC). Compared to HBV preS deletion, the oncogenic effect of preS combo mutation has rarely been investigated. With a cohort including 2114 subjects, we demonstrated that preS combo mutations G2950A/G2951A/A2962G/C2964A and C3116T/T31C significantly increased the risk of HCC in patients without antiviral treatment, whereas preS2 deletion significantly increased the risk of HCC in patients with antiviral treatment. The prevalence of C3116T/T31C (43.61%) was higher than preS2 deletion (7.16%). By using Sleeping Beauty mouse models and in vitro experiments, we found G2950A/G2951A/A2962G/C2964A, C3116T/T31C, and preS2 deletion promoted hepatocarcinogenesis by increasing levels of inflammatory cytokines, activating STAT3 pathway, enhancing endoplasmic reticulum stress, and altering gene expression profiles in inflammation- and metabolism-related pathways. These results suggest that preS combo mutations G2950A/G2951A/A2962G/C2964A and C3116T/T31C had similar oncogenic effects of preS2 deletion and should also be monitored.

Abstract

This study aimed to elucidate the effects and underlying mechanisms of hepatitis B virus (HBV) preS mutations on hepatocarcinogenesis. The effect of the preS mutations on hepatocellular carcinoma (HCC) occurrence was evaluated using a prospective cohort study with 2114 HBV-infected patients, of whom 612 received antiviral treatments. The oncogenic functions of HBV preS mutations were investigated using cancer cell lines and Sleeping Beauty (SB) mouse models. RNA-sequencing and microarray were applied to identify key molecules involved in the mutant-induced carcinogenesis. Combo mutations G2950A/G2951A/A2962G/C2964A and C3116T/T31C significantly increased HCC risk in patients without antiviral treatment, whereas the preS2 deletion significantly increased HCC risk in patients with antiviral treatment. In SB mice, the preS1/preS2/S mutants induced a higher rate of tumor and higher serum levels of inflammatory cytokines than did wild-type counterpart. The preS1/preS2/S mutants induced altered gene expression profiles in the inflammation- and metabolism-related pathways, activated pathways of endoplasmic reticulum (ER) stress, affected the response to hypoxia, and upregulated the protein level of STAT3. Inhibiting the STAT3 pathway attenuated the effects of the preS1/preS2/S mutants on cell proliferation. G2950A/G2951A/A2962G/C2964A, C3116T/T31C, and preS2 deletion promote hepatocarcinogenesis via inducing ER stress, metabolism alteration, and STAT3 pathways, which might be translated into HCC prophylaxis.

HBV variants are common in the 'immune-tolerant' phase of chronic hepatitis B

Nucleos(t)ide analogues (NUC) treatment prevents progression of liver fibrosis in subjects with chronic hepatitis B (CHB). However, risk of hepatocellular carcinoma (HCC) persists despite viral suppression. Specific HBV variants have been associated with adverse outcomes, including HCC; however, the frequency of these variants during the seemingly benign immunotolerant (IT) phase is unknown. Next-generation sequencing and detailed virological characterization on a cohort of treatment-naïve IT subjects were performed to determine the frequency of clinically relevant viral variants. Samples from 97 subjects (genotype B/C 55%/45%, median HBV-DNA 8.5 log₁₀ IU/mL, median HBsAg 4.8 log₁₀  IU/mL, median HBeAg 3.6 log₁₀  PEIU/mL) were analysed. Despite subjects being in the IT phase, clinically relevant HBV variants were common at baseline, particularly in the basal core promoter (BCP, overlaps the hepatitis B X (HBx) gene), precore and PreS regions. BCP/HBx variants were independently associated with lower baseline HBeAg, HBsAg and HBV-DNA titres. Precore variants were independently associated with higher baseline ALT. Increased viral diversity was associated with increased age and lower HBV-DNA, HBsAg and HBeAg levels. Low-level (<5%) drug resistance-associated amino acid substitutions in the HBV reverse transcriptase were detected in 9 (9%) subjects at pre-treatment but were not associated with reduced antiviral activity. Future studies should evaluate whether the detection of HBV variant during IT CHB is predictive of progression to immune clearance and poor prognosis, and whether early initiation of antiviral therapy during IT CHB to prevent the selection of HBV variants is clinically beneficial.

A comparative study of hepatitis B virus X protein mutants K130M, V131I and KV130/131MI to investigate their roles in fibrosis, cirrhosis and hepatocellular carcinoma

Hepatitis B virus (HBV) genomic mutations A1762T, G1764A and AG1762/1764TA cause production of HBV X protein (HBx) mutants, namely K130M, V131I and KV130/131MI. These mutations are important biomarkers for the development of cirrhosis and hepatocellular carcinoma (HCC) in chronic HBV patients. This study comparatively analyses the impact of intracellular expression of HBx mutants on HCC cell line Huh7. It was found that expression of KV130/131MI induced: cell proliferation, altered expression of cell cycle regulatory genes in favour of cell proliferation, intracellular reactive oxygen species (ROS) production and mitochondrial depolarization. KV130/131MI may be directly involved in host cell proliferation and hepatocarcinogenesis via altering expression of cell cycle regulatory genes. KV130/131MI may also play pivotal roles in fibrosis and cirrhosis via inducing ROS production and mitochondrial depolarization. Furthermore, these might be the possible reasons for higher occurrence of AG1762/1764TA as compared to A1762T and G1764A in cirrhosis and HCC patients.

Hepatocellular carcinoma-associated single-nucleotide variants and deletions identified by the use of genome-wide high-throughput analysis of hepatitis B virus

This study investigated hepatitis B virus (HBV) single-nucleotide variants (SNVs) and deletion mutations linked with hepatocellular carcinoma (HCC). Ninety-three HCC patients and 108 non-HCC patients were enrolled for HBV genome-wide next-generation sequencing (NGS) analysis. A systematic literature review and a meta-analysis were performed to validate NGS-defined HCC-associated SNVs and deletions. The experimental results identified 60 NGS-defined HCC-associated SNVs, including 41 novel SNVs, and their pathogenic frequencies. Each SNV was specific for either genotype B (n = 24) or genotype C (n = 34), except for nt53C, which was present in both genotypes. The pathogenic frequencies of these HCC-associated SNVs showed a distinct U-shaped distribution pattern. According to the meta-analysis and literature review, 167 HBV variants from 109 publications were categorized into four levels (A-D) of supporting evidence that they are associated with HCC. The proportion of NGS-defined HCC-associated SNVs among these HBV variants declined significantly from 75% of 12 HCC-associated variants by meta-analysis (Level A) to 0% of 10 HCC-unassociated variants by meta-analysis (Level D) (P < 0.0001). PreS deletions were significantly associated with HCC, in terms of deletion index, for both genotypes B (P = 0.030) and C (P = 0.049). For genotype C, preS deletions involving a specific fragment (nt2977-3013) were significantly associated with HCC (HCC versus non-HCC, 6/34 versus 0/32, P = 0.025). Meta-analysis of preS deletions showed significant association with HCC (summary odds ratio 3.0; 95% confidence interval 2.3-3.9). Transfection of Huh7 cells showed that all of the five novel NGS-defined HCC-associated SNVs in the small surface region influenced hepatocarcinogenesis pathways, including endoplasmic reticulum-stress and DNA repair systems, as shown by microarray, real-time polymerase chain reaction and western blot analysis. Their carcinogenic mechanisms are worthy of further research. Copyright © 2017 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.

LUC7L3/CROP inhibits replication of hepatitis B virus via suppressing enhancer II/basal core promoter activity

The core promoter of hepatitis B virus (HBV) genome is a critical region for transcriptional initiation of 3.5 kb, pregenome and precore RNAs and for the viral replication. Although a number of host-cell factors that potentially regulate the viral promoter activities have been identified, the molecular mechanisms of the viral gene expression, in particular, regulatory mechanisms of the transcriptional repression remain elusive. In this study, we identified LUC7 like 3 pre-mRNA splicing factor (LUC7L3, also known as hLuc7A or CROP) as a novel interacting partner of HBV enhancer II and basal core promoter (ENII/BCP), key elements within the core promoter, through the proteomic screening and found that LUC7L3 functions as a negative regulator of ENII/BCP. Gene silencing of LUC7L3 significantly increased expression of the viral genes and antigens as well as the activities of ENII/BCP and core promoter. In contrast, overexpression of LUC7L3 inhibited their activities and HBV replication. In addition, LUC7L3 possibly contributes to promotion of the splicing of 3.5 kb RNA, which may also be involved in negative regulation of the pregenome RNA level. This is the first to demonstrate the involvement of LUC7L3 in regulation of gene transcription and in viral replication.

Naturally occurring basal core promoter A1762T/G1764A dual mutations increase the risk of HBV-related hepatocellular carcinoma: a meta-analysis

Basal core promoter (BCP) A1762T/G1764A dual mutations in hepatocarcinogenesis remain controversial. Published studies up to June 1, 2015 investigating the frequency of A1762T/G1764A dual mutations from chronic hepatitis B virus (HBV) infection, including hepatocellular carcinoma (HCC), were systematically identified. A total of 10,240 patients with chronic HBV infection, including 3729 HCC cases, were included in 52 identified studies. HCC patients had a higher frequency of BCP A1762T/G1764A dual mutations compared with asymptomatic HBsAg carriers (ASC) and patients with chronic hepatitis B (CHB) and liver cirrhosis (LC) (OR = 5.59, P < 0.00001; OR = 2.87, P < 0.00001; OR = 1.55, P = 0.02, respectively). No statistically significant difference was observed in the frequency of A1762T/G1764A dual mutations in cirrhotic HCC versus non-cirrhotic HCC patients (OR = 2.06, P = 0.05). Chronic HBV-infected patients and HCC patients with genotype B had a significantly lower risk of A1762T/G1764A dual mutations compared with patients with genotype C (OR = 0.30, P < 0.0001 and OR = 0.34, P = 0.04, respectively). In HBV genotype C subjects, A1762T/G1764A dual mutations contributed to significantly higher risk for HCC developing compared with non-mutation ones (OR = 3.47, P < 0.00001). In conclusion, A1762T/G1764A dual mutations increase the risk of HBV-related hepatocellular carcinoma, particularly in an HBV genotype C population, even without progression to cirrhosis.

Clinical significance of hepatitis B surface antigen mutants

Hepatitis B virus (HBV) infection is a major public health problem in many countries, with nearly 300 million people worldwide carrying HBV chronic infection and over 1 million deaths per year due to cirrhosis and liver cancer. Several hepatitis B surface antigen (HBsAg) mutations have been described, most frequently due to a single amino acid substitution and seldom to a nucleotide deletion. The majority of mutations are located in the S region, but they have also been found in the pre-S1 and pre-S2 regions. Single amino acid substitutions in the major hydrophilic region of HBsAg, called the “a” determinant, have been associated with immune escape and the consequent failure of HBV vaccination and HBsAg detection, whereas deletions in the pre-S1 or pre-S2 regions have been associated with the development of hepatocellular carcinoma. This review article will focus on the HBsAg mutants and their biological and clinical implications.

Quantitative evaluation of hepatitis B virus mutations and hepatocellular carcinoma risk: a meta-analysis of prospective studies

BACKGROUND

The temporal relationship between hepatitis B virus (HBV) mutations and hepatocellular carcinoma (HCC) remains unclear.

METHODS

We conducted a meta-analysis including cohort and nested case-control studies to prospectively examine the HCC risk associated with common variants of HBV in the PreS, Enhancer II, basal core promoter (BCP) and precore regions. Pertinent studies were identified by searching PubMed, Web of Science and the Chinese Biological Medicine databases through to November 2014. Study-specific risk estimates were combined using fixed or random effects models depending on whether significant heterogeneity was detected.

RESULTS

Twenty prospective studies were identified, which included 8 cohort and 12 nested case-control studies. There was an increased risk of HCC associated with any PreS mutations with a pooled relative risk (RR) of 3.82 [95% confidence interval (CI): 2.59-5.61]. The pooled-RR for PreS deletion was 3.98 (95% CI: 2.28-6.95), which was higher than that of PreS2 start codon mutation (pooled-RR=2.63, 95% CI: 1.30-5.34). C1653T in Enhancer II was significantly associated with HCC risk (pooled-RR=1.83; 95% CI: 1.21-2.76). For mutations in BCP, statistically significant pooled-RRs of HCC were obtained for T1753V (pooled-RR=2.09; 95% CI: 1.49-2.94) and A1762T/G1764A double mutations (pooled-RR=3.11; 95% CI: 2.08-4.64). No statistically significant association with HCC risk was observed for G1896A in the precore region (pooled-RR=0.77; 95% CI: 0.47-1.26).

CONCLUSIONS

This study demonstrated that PreS mutations, C1653T, T1753V, and A1762T/G1764A, were associated with an increased risk of HCC. Clinical practices concerning the HCC risk prediction and diagnosis may wish to focus on patients with these mutations.

Influence of B cells in liver fibrosis associated with hepatitis B virus harboring basal core promoter mutations

The development of the liver disease in chronic hepatitis B with common viral variants can be determined through the interaction between the virus and the host immune response. B cells constitute half of the intrahepatic lymphocyte population with an impact on fibrosis. A proliferation-inducing ligand (APRIL) has been shown to have a co-stimulatory activity on B cells. For this study HBV DNA was amplified and then sequenced to show the presence of the basal core promoter (BCP) mutations in the serum from 57 patients with chronic hepatitis B. The range of IgD-positive B cells was detected by immunohistochemistry in liver biopsies; and patients serum was assayed for APRIL levels by enzyme immunoassay. Twenty-seven patients (47.4%) harbored the A1762T-G1764A BCP mutations. Coefficients of logistic regression showed that the effect of increasing IgD-positive B cells in rising odds of the liver disease is the same in the patients with BCP mutation A1762T-G1764A and in the patients without mutation, nevertheless the effect of APRIL is not similar in these two groups of patients. Logistic regression in patients with BCP A1762T-G1764A mutations demonstrated that increasing one score of APRIL decreased the odds of fibrosis stage about 8%. These results suggest that in infection with viral variants of hepatitis B virus, the population of IgD-positive B cells may play a decisive role in later stages of the liver disease which is reduced by APRIL in chronic hepatitis patients with BCP mutations.

Management of hepatitis B: Consensus of the Japan Society of Hepatology 2009

Recently, much progress has been made in the field of hepatitis B, such as natural history of the disease in relation to the amount of hepatitis B virus (HBV) DNA, genotypes of HBV influencing the natural course and treatment effects, mutations of HBV influencing the severity of the disease and development of hepatocellular carcinoma, and antiviral treatment such as nucleos(t)ide analogues and pegylated interferon. To make the consensus for the diagnosis, management and treatment of hepatitis B, a meeting was held during 45th annual meeting of Japan Society of Hepatology (JSH) in June 2009. In the meeting, recommendations and informative statements were discussed on the following subjects: (i) natural history of HBV infection; (ii) clinical implication of HBV genotypes; (iii) HBV mutations and their potential impact on pathogenesis of HBV infection; (iv) indications for antiviral treatment of chronic hepatitis B; (v) nucleos(t)ide analogues for chronic hepatitis B; and (vi) interferon therapy for chronic hepatitis B. The presenters reviewed the data on these subjects and proposed the consensus statements and recommendations. These statements were discussed among the organizers and presenters, and were approved by the participants of the meeting. In the current report, the relevant data were reviewed and the 12 consensus statements and nine recommendations on chronic hepatitis B were described.

Comparison study on the complete sequence of hepatitis B virus identifies new mutations in core gene associated with hepatocellular carcinoma

BACKGROUND

Mutations in the hepatitis B virus (HBV) genome may influence the activity of liver disease. The aim of this study was to identify new viral variations associated with hepatocellular carcinoma (HCC).

METHODS

We carried out a comparison study on the complete sequence of HBV isolated from 20 HCC and 35 non-HCC patients in Qidong, China, an area with a high incidence of HCC. We compared the HBV sequences in a consecutive series of plasma samples from four HCC cases before and after the occurrence of HCC. In addition, we selected four mutations in the HBV core (C) gene to verify their relationships to HCC in an independent set of 103 HCC cases and 103 sex- and age-matched non-HCC controls.

RESULTS

The pre-S deletion and 12 point mutations, namely, the pre-S2 start codon mutation, T53C in the pre-S2 gene, T766A in the S gene, G1613A, C1653T, A1762T, G1764A in the X gene, and G1899A, C2002T, A2159G, A2189C, and G2203W (A or T) in the pre-C/C gene, showed close associations with HCC. In the validation study, A2159G, A2189C, and G2203W showed consistent associations with HCC by univariate analysis. Multivariate analysis showed that A2189C and G2203W were independent risk factors for HCC. The odds ratios (95% confidence interval) were 3.99 (1.61-9.92) and 9.70 (1.17-80.58), respectively, for A2189C and G2203W.

CONCLUSIONS

These results implicate A2189C and G2203W as new predictive markers for HCC.

IMPACT

The complete genome analysis of HBV provided pilot data for the identification of novel mutations that could serve as markers for HCC.

HBV mutations in untreated HIV-HBV co-infection using genomic length sequencing

HIV infection has a significant impact on the natural progression of hepatitis B virus (HBV) related liver disease. In HIV-HBV co-infected patients, little is known about mutations in the HBV genome, which can influence severity of liver disease. The aim of this study was to characterize and to determine the frequency of known clinically significant mutations in the HBV genomes from HIV-HBV co-infected patients and from HBV mono-infected patients. To accomplish this, genomic length HBV sequencing was performed in highly-active anti-retroviral therapy (HAART)-naïve HIV-HBV co-infected patients (n=74) and in anti-HBV therapy-naïve HBV mono-infected patients (n=55). The frequency of HBV mutations differed between the co-infected and mono-infected patients when comparing patients with the same genotype. BCP mutations A1762T and G1764A were significantly more frequent in HBV genotype C mono-infection and the -1G frameshift was significantly more frequent in co-infection and was only observed in HBV genotype A co-infection. PreS2 deletions were observed more frequently in the setting of co-infection. Further work is needed to determine if these mutational patterns influence the differences in liver disease progression in HIV-HBV co-infected and HBV mono-infected patients.

Subgenotypes of hepatitis B virus genotype D (D1, D2, D3 and D5) in India: differential pattern of mutations, liver injury and occult HBV infection

Hepatitis B genotype D (HBV/D) is the most widespread genotype and exists as at least five subgenotypes (HBV/D1-D5). However, little is known about the association of virological characteristics with clinical differences among HBV/D subgenotypes. To investigate the virological characteristics of these subgenotypes and their clinical implications, we selected a cohort of 109 genotype D infected individuals from the state of West Bengal, India, including 68 HBsAg positive patients and 41 with occult HBV infection. Among the HBsAg positive subjects 28 had chronic hepatitis B virus infection, 40 were asymptomatic carriers based on clinical examination, liver function test and ultrasonograph results. Overall, HBV/D1 was found in 17%, HBV/D2 in 29%, HBV/D3 in 34% and HBV/D5 in 20% of the cases. HBV/D1 was significantly associated with chronic liver disease (P = 0.01), and in this subgenotype A1896 (PreC mutations) were most common. Although BCP mutations (A/C1753 and T1762/A1764) were found to be frequently associated with HBV/D2 (33% and 33%) and D5 (47% and 59%), no apparent clinical correlation was observed. On the other hand, occult HBV infection was significantly associated with HBV/D3 infection, along with low level of BCP and PreC mutations and several non-synonymous substitutions in the catalytic reverse transcriptase (RT) domain of polymerase gene. Similar nucleotide substitutions in the surface (S) gene region were observed from both northern and eastern Indian HBV/D3 isolates. In conclusion, HBV/D subgenotypes differ in their mutational patterns in the S, polymerase and the BCP/PreC regions that may influence their clinical outcomes.

Association of concurrent hepatitis B surface antigen and antibody to hepatitis B surface antigen with hepatocellular carcinoma in chronic hepatitis B virus infection

Antibody to hepatitis B surface antigen (HBsAg) (anti-HBs) can exist in patients with chronic hepatitis B virus (HBV) infection. To date, little is known about the association of concurrent HBsAg and anti-HBs (concurrent HBsAg/ anti-HBs) with hepatocellular carcinoma (HCC). The aim of this study was to investigate the clinical relevance of concurrent HBsAg/anti-HBs with preS deletion mutations and HCC in chronic HBV infection. A total of 755 patients with chronic HBV infection were included consecutively at a tertiary center. Logistic regression analysis was used to identify risk factors for HCC, and serum HBV DNA was amplified, followed by direct sequencing to detect preS deletions. The prevalence of concurrent HBsAg/anti-HBs was 6.4% (48/755) and all HBVs tested were genotype C. HCC occurred more frequently in the concurrent HBsAg/anti-HBs group than in the HBsAg only group [22.9% (11/48) vs. 7.9% (56/707), P = 0.002]. In multivariate analyses, age >40 years [odds ratio (OR), 14.712; 95% confidence interval (CI), 4.365-49.579; P < 0.001], male gender (OR 2.431; 95% CI, 1.226-4.820; P = 0.011), decompensated cirrhosis (OR, 3.642; 95% CI, 1.788-7.421; P < 0.001) and concurrent HBsAg/anti-HBs (OR, 4.336; 95% CI, 1.956-9.613; P < 0.001) were associated independently with HCC. In molecular analysis, preS deletion mutations were more frequent in the concurrent HBsAg/anti-HBs and HCC groups than in the HBsAg without HCC group (42.3% and 32.5% vs. 11.3%; P = 0.002 and 0.012, respectively). In conclusion, concurrent HBsAg/anti-HBs is associated with preS deletion mutations and may be one of the risk factors for HCC in chronic HBV infection with genotype C.

Associations between hepatitis B virus mutations and the risk of hepatocellular carcinoma: a meta-analysis

Background

The association between hepatitis B virus (HBV) mutations and hepatocarcinogenesis remains controversial because of conflicting data in the literature. We conducted a meta-analysis of case–control and cohort studies to examine HBV PreS, enhancer II (EnhII), basal core promoter (BCP), and precore mutations in relation to the risk of hepatocellular carcinoma (HCC).

Methods

We searched databases for studies of these associations that were published in English or Chinese up to August 31, 2008. HBV mutation–specific odds ratios and relative risks were pooled by use of a random-effects model and stratified by potential confounders. All statistical tests were two-sided.

Results

Of the 43 studies included in this meta-analysis, 40 used a case–control design. The 43 studies evaluated a total of 11 582 HBV-infected participants, of whom 2801 had HCC. Statistically significant summary odds ratios of HCC were obtained for any PreS mutation (3.77, 95% confidence interval [CI] = 2.57 to 5.52), C1653T in EnhII (2.76, 95% CI = 2.09 to 3.64), T1753V (2.35, 95% CI = 1.63 to 3.40), and A1762T/G1764A in BCP (3.79, 95% CI = 2.71 to 5.29). PreS mutations were more strongly associated with an increased risk of HCC in subjects who were infected with HBV genotype C than in those who were infected with HBV genotype B, whereas the opposite was true for A1762T/G1764A. C1653T, T1753V, and A1762T/G1764A were more strongly associated with an increased risk of HCC in hepatitis B e antigen (HBeAg)–positive subjects than in HBeAg-negative subjects. PreS mutations, C1653T, T1753V, and A1762T/G1764A accumulated during the progression of chronic HBV infection from the asymptomatic carrier state to HCC (P_trend < .001 for each mutation). PreS mutations, C1653T, C1653T + T1753V, and A1762T/G1764A-based combinations of mutations had specificities greater than 80% for the prediction of HCC. The precore mutations G1896A and C1858T were not associated with the risk of HCC, regardless of HBeAg status and HBV genotype.

Conclusions

HBV PreS mutations, C1653T, T1753V, and A1762T/G1764A are associated with an increased risk of HCC. These mutations alone and in combination may be predictive for hepatocarcinogenesis.

Associations between hepatitis B virus mutations and the risk of hepatocellular carcinoma: a meta-analysis

BACKGROUND

The association between hepatitis B virus (HBV) mutations and hepatocarcinogenesis remains controversial because of conflicting data in the literature. We conducted a meta-analysis of case-control and cohort studies to examine HBV PreS, enhancer II (EnhII), basal core promoter (BCP), and precore mutations in relation to the risk of hepatocellular carcinoma (HCC).

METHODS

We searched databases for studies of these associations that were published in English or Chinese up to August 31, 2008. HBV mutation-specific odds ratios and relative risks were pooled by use of a random-effects model and stratified by potential confounders. All statistical tests were two-sided.

RESULTS

Of the 43 studies included in this meta-analysis, 40 used a case-control design. The 43 studies evaluated a total of 11 582 HBV-infected participants, of whom 2801 had HCC. Statistically significant summary odds ratios of HCC were obtained for any PreS mutation (3.77, 95% confidence interval [CI] = 2.57 to 5.52), C1653T in EnhII (2.76, 95% CI = 2.09 to 3.64), T1753V (2.35, 95% CI = 1.63 to 3.40), and A1762T/G1764A in BCP (3.79, 95% CI = 2.71 to 5.29). PreS mutations were more strongly associated with an increased risk of HCC in subjects who were infected with HBV genotype C than in those who were infected with HBV genotype B, whereas the opposite was true for A1762T/G1764A. C1653T, T1753V, and A1762T/G1764A were more strongly associated with an increased risk of HCC in hepatitis B e antigen (HBeAg)-positive subjects than in HBeAg-negative subjects. PreS mutations, C1653T, T1753V, and A1762T/G1764A accumulated during the progression of chronic HBV infection from the asymptomatic carrier state to HCC (P(trend) < .001 for each mutation). PreS mutations, C1653T, C1653T + T1753V, and A1762T/G1764A-based combinations of mutations had specificities greater than 80% for the prediction of HCC. The precore mutations G1896A and C1858T were not associated with the risk of HCC, regardless of HBeAg status and HBV genotype.

CONCLUSIONS

HBV PreS mutations, C1653T, T1753V, and A1762T/G1764A are associated with an increased risk of HCC. These mutations alone and in combination may be predictive for hepatocarcinogenesis.

Specific mutations in the enhancer II/core promoter/precore regions of hepatitis B virus subgenotype C2 in Korean patients with hepatocellular carcinoma

Recently, hepatitis B virus (HBV) genotypes and mutations have been reported to be related to hepatocellular carcinoma (HCC). This cross-sectional case-control study examined the relationship between HCC and mutations in the enhancer II/core promoter and precore regions of HBV by comparing 135 Korean HCC patients infected with HBV genotype C2 (HBV/C2; HCC group) with 135 age-, sex-, and hepatitis B e antigen (HBeAg) status-matched patients without HCC (non- HCC group). Age and sex were also matched between HBeAg-positive and -negative patients. The prevalence of T1653, A1689, V1753, T1762/A1764, T1846, A1850, C1858, and A1896 mutations was evaluated in this population. The prevalence of the T1653 mutation in the box alpha region, the T1689 [corrected] mutation in between the box alpha and beta regions, and the T1762/A1764 mutations in the basal core promoter region was significantly higher in the HCC group compared to the non-HCC group (8.9% vs. 2.2%, P = 0.017; 19.3% vs. 4.4%, P < 0.001; and 60.7% vs. 22.2%; P < 0.001). Among HBeAg-negative patients, the frequency of the T1653 mutation was higher in the HCC group. Regardless of HBeAg status, the prevalence of the T1689, [corrected] and T1762/A1764 mutations was higher in the HCC group than in the non-HCC group. However, no association was observed between mutations in the precore region and HCC. Upon multivariate analysis, the presence of the T1653, T1689, [corrected] and T1762/A1764 mutations was an independent predictive factor for HCC. The addition of the T1653 or T1689 [corrected] mutation to T1762/A1764 increased the risk of HCC. In conclusion, the T1653, T1689, [corrected] and/or T1762/A1764 mutations were associated with the development of HCC in Korean patients infected with HBV/C2.

Sequential accumulation of the mutations in core promoter of hepatitis B virus is associated with the development of hepatocellular carcinoma in Qidong, China

BACKGROUND/AIMS

To investigate the mutations in hepatitis B virus (HBV) that might be related to hepatocellular carcinoma (HCC) in the high-risk area Qidong, China.

METHODS

DNA sequences of HBV basal core promoter (BCP) and the overlapping X gene were determined in 58 HCC and 71 chronic hepatitis (CH) patients. In addition, a consecutive series of plasma samples from 15 HCC cases were employed to compare the CP/X sequences before and after the occurrence of HCC.

RESULTS

T1762/A1764 double mutation was frequently found in Qidong patients, regardless of clinical status (65.5% in HCC and 73.2% in CH, P>0.05). Unexpectedly, the adjacent T1766/A1768 mutation significantly increased the risk of HCC (P<0.05). Moreover, the prevalence of triple mutations in BCP was significantly higher in patients with HCC than those with CH (P<0.05). The longitudinal study demonstrated that the mutations in BCP were gradually accumulated during the development of HCC. Colony formation assay showed while A1764 mutation alone did not alter the colony-inhibitory activity of HBx, double or triple mutations largely abrogated this effect.

CONCLUSIONS

The complex mutation involving T1766/A1768 was closely related to HCC. The enhanced risk of HCC caused by BCP variants could be attributable partially to the aberrant activity of HBx.

Repeated passage of wild-type woodchuck hepatitis virus in lymphoid cells does not generate cell type-specific variants or alter virus infectivity

Woodchuck hepatitis virus (WHV), which is closely related to human hepatitis B virus, infects the liver but also invariably establishes persistent infection in the lymphatic system. Although the dose of invading virus appears to be the main factor in determining whether WHV infection is restricted to the lymphatic system or also engages the liver, the nature of WHV lymphotropism remains unclear and a role for a specific lymphotropic variant was not excluded. The availability of woodchuck lymphocyte and hepatocyte cultures susceptible to WHV infection allows investigation of this issue in vitro. We hypothesized that repeated passage of wild-type WHV in lymphoid cells should lead to enrichment of a lymphotropic virus variant, if in fact such a variant exists. For this purpose, wild-type WHV with a homogeneous sequence was used as the inoculum, while lymphoid cells from a single healthy woodchuck donor and a normal woodchuck WCM-260 hepatocyte line served as infection targets. The serial passage of the wild-type virus repeated up to 13 times for both cell types did not lead to the emergence of cell type-specific WHV variants, as revealed by sequence analysis of the virus envelope and the core and X gene sequences. Moreover, the virus passaged in both cell types remained infectious for naive woodchucks, produced infection profiles that depended upon virus dose but not on virus cellular origin, and retained its initial DNA sequence. These results imply that WHV lymphotropism is a natural propensity of the wild-type virus and is not a consequence of infection with a viral variant.

Influence of hepatitis B virus X and core promoter mutations on hepatocellular carcinoma among patients infected with subgenotype C2

Hepatitis B virus (HBV) genotypes/subgenotypes and their related mutations in the HBV genome have been reported to be associated with hepatocellular carcinoma (HCC). To determine the HCC-associated mutations of the HBV genome in the entire X, core promoter, and precore/core regions, a cross-sectional control study was conducted comparing 80 Japanese patients infected with HBV C2 and suffering from HCC with 80 age-, sex-, and hepatitis B e antigen (HBeAg) status-matched patients without HCC (non-HCC group). Each HBeAg-positive group (31 with HCC; 29 without HCC) and HBeAg-negative group (49 with HCC; 51 without HCC) was also matched with respect to age and sex. The C1479, T1485, H1499, A1613, T1653, V1753, T1762/A1764, and A1896 mutations were frequent in this population. The prevalences of the T1653 mutation in the box alpha region and the V1753 and T1762/A1764 mutations in the basal core promoter region were significantly higher in the HCC group than in the non-HCC group (56% versus 30%, 50% versus 24%, and 91% versus 73% [P = 0.0013, P = 0.0010, and P = 0.0035, respectively]). The platelet count was significantly lower for the HCC group than for the non-HCC group (10.7 x 10(4) +/- 5.1 x 10(4) versus 17.3 x 10(4) +/- 5.1 x 10(4) platelets/mm(3) [P < 0.0001]). Regardless of HBeAg status, the prevalence of the T1653 mutation was higher in the HCC group (52% versus 24% [P = 0.036] for HBeAg-positive patients and 59% versus 33% [P = 0.029] for HBeAg-negative patients). In the multivariate analysis, the presence of T1653, the presence of V1753, and a platelet count of < or =10 x 10(4)/mm(3) were independent predictive factors for HCC (odds ratios [95% confidence intervals], 4.37 [1.53 to 12.48], 7.98 [2.54 to 25.10], and 24.39 [8.11 to 73.33], respectively). Regardless of HBeAg status, the T1653 mutation increases the risk of HCC in Japanese patients with HBV/C2.

Association of pre-S deletion mutant of hepatitis B virus with risk of hepatocellular carcinoma

BACKGROUND

Pre-S deletion mutant of hepatitis B virus (HBV) affects the expression of middle and small surface proteins, resulting in intracellular accumulation of large surface protein. The correlation between pre-S deletion mutant and risk of hepatocellular carcinoma (HCC) in hepatitis B virus carriers remains unclear.

METHODS

Using molecular assays, pre-S deletion mutant of HBV were determined in 266 patients with chronic HBV genotype B or C infection. They included 202 asymptomatic carriers and 64 HCC patients.

RESULTS

The overall prevalence of pre-S deletion mutant was 16.5%. Hepatocellular carcinoma (odds ratio [OR], 3.23; 95% confidence interval [CI], 1.23-8.48, P = 0.02) and genotype C (OR, 3.19; 95%CI, 1.54-6.62, P = 0.002) were independently associated with the presence of pre-S deletion mutant. The prevalence of pre-S deletion mutant was comparable between HCC patients with genotype B and C infection. Nevertheless, in asymptomatic carriers, patients with genotype C infection were significantly associated with the presence of pre-S deletion mutant compared to those with genotype B infection (20.8% vs 7.2%, P = 0.007). Compared with age- and genotype B-matched asymptomatic carriers, young HCC patients (<50 years of age) had a significantly higher frequency of pre-S deletion (3.4% vs 20%, P = 0.04).

CONCLUSIONS

Pre-S deletion mutant is more frequent in HBV carriers with genotype C infection, and those with pre-S deletion mutant may be associated with the development of HCC, irrespective of HBV genotype.

Hepatitis B virus (HBV) genotypes/subgenotypes in China: mutations in core promoter and precore/core and their clinical implications

BACKGROUND

The association of hepatitis B virus (HBV) genotypes with clinical course of infection is increasingly recognized.

OBJECTIVES

In order to investigate the genetic diversity of HBV and its clinical implications, 241 HBV-infected patients including 34 with hepatocellular carcinoma (HCC) were enrolled in this study.

METHODS

HBV genotyping was performed with an ELISA assay. HBV subgenotypes were determined by PCR-RFLP. HBV core promoter/precore/core mutations were analyzed by direct sequencing.

RESULTS

The overall prevalence of HBV/B and C was 65% and 33%, respectively. Among HBV/C, 42% were Cs/C1 and 58% were Ce/C2. The HBV/C1 was only found in the patients originating from Southern China (p=0.0001). Among HCC patients, HBV/C2 was only found in the elder age group (> or =51 years; p<0.05) and HBV/Ba was associated with young HCC patients (<35 years). Mutations associated with HCC were V1753 and T1762/A1764 (p<0.01). The prevalence of the V1753 was higher in HBV/C1 strains (p<0.04), A1898 was only found among HBV/C1 (p=0.056). T1762/A1764 was frequently demonstrated in both subgenotypes. The T1858 (90%) and A1896 (40%) mutations were most frequent in HBV/C2 (p<0.008).

CONCLUSIONS

HBV/C1 and HBV/C2 have distinct geographic distributions in China. V1753 in addition to T1762/A1764 double mutation in the basal core promoter region seems to be associated with HCC development, especially in the patients with HBV/C1.

Prevalence of hepatitis B virus genotype D in precore mutants among chronic liver disease patients from New Delhi, India

Hepatitis B is one of the most important causes of chronic viral hepatitis world wide. Mutations in the precore region of the hepatitis B virus (HBV) genome are frequently found in hepatitis B envelope antigen-negative cases. Data from India on the HBV genotype-associated distribution of precore mutations are limited. Our objective in this study was to genotype and detect the precore mutant with a point mutation from G to A at nucleotide 1896 using ligase chain reaction (LCR) and direct sequencing. A total of 115 cases of chronic liver disease were screened. The cases were evaluated on the basis of history, clinical examination, liver function profile, and serological test for HBV infection, which includes HBsAg, anti HBcIgG, HBeAg using commercially available ELISA kits. The cases, which were HBeAg+, HBeAg-, and HBV DNA+, were subjected to LCR and confirmed by direct sequencing. Of 115 chronic liver disease cases, 50 (43.5%) cases were HBV DNA positive. All cases were subjected to LCR; 11 (22%) cases confirmed the presence of precore mutants, while the remaining 39 (78%) were classified as the wild form of the virus. HBV genotyping by direct sequencing revealed that genotype D was predominant in both wild and mutant forms of the virus. We conclude that the HBV genotype distribution was not significantly different between precore mutants and the wild form of the virus (P>0.05). North Indian patients with genotype D were more likely to have persistent HBV infection with precore mutants. HBV genotypes correlate with the clinical outcome of chronic HBV infection.

Specific mutations in enhancer II/core promoter of hepatitis B virus subgenotypes C1/C2 increase the risk of hepatocellular carcinoma

BACKGROUND/AIMS

Hepatitis B virus genotype C (HBV/C) has been classified into two geographically distinct subgenotypes; HBV/C1/Cs (Southeast Asia) and HBV/C2/Ce (East Asia).

METHODS

Viral differences in enhancer II/core promoter and precore regions between the subgenotypes and their association with hepatocellular carcinoma (HCC) were assessed in a matched cross-sectional control study of 118 carriers (from Hong Kong) with HBV/C1/Cs (48.0 years, 81% male, 40% HBeAg+, 44% HCC) and 210 HBV/C2/Ce (172 from Japan, 38 from Hong Kong) (50.2 years, 78% male, 30% HBeAg+, 46% HCC).

RESULTS

Univariate analyses showed that mutation V1753 was predictive for HCC among HBeAg-positive-C1/Cs-carriers (P=0.0055), and T1653 among HBeAg-positive-C2/Ce-carriers (P=0.018), and T1653 or V1753 or T1762/A1764 among HBeAg-negative-C2/Ce-carriers (P<0.05). In the multivariate analysis on all HBV/C subjects, independent predictive factors for HCC were subgenotype C2/Ce (odds ratio, 4.21; 95% confidence interval, 1.07-16.23), T1653 (3.64; 1.93-6.86), V1753 (3.07; 1.66-5.65) and T1762/A1764 (2.58; 1.21-5.49) mutations, age (50 years), gender (male) and HBeAg (positive).

CONCLUSIONS

Our data indicate that T1653 and/or V1753 mutations in addition to T1762/A1764 are differently associated with HCC in context of HBeAg status among HBV/C1/Cs and C2/Ce-carriers. HBV/C subgenotypes have specific mutation patterns, which is probably responsible for increased carcinogenesis of HBV/C2/Ce.

Virological analysis, genotypes and mutational patterns of the HBV precore/core gene in HBV/HCV-related hepatocellular carcinoma

We investigated the replicative profile of hepatitis B (HBV) and hepatitis C (HCV) viruses and the mutational pattern of the HBV precore/core (pre-C/C) domain in hepatocellular carcinoma (HCC). Thirty-eight consecutive patients with HCC were included in the study - 18 of them with HBV/HCV co-infection and 20 with HBV single infection. Twenty-three additional patients with co-infection, without HCC were recruited as the control group. Replication activity was evaluated by detecting and quantitating both HBV and HCV genomes. The HBV pre-C/C region, encompassing the pregenome encapsidation signal involved in viral replication, was analysed by direct sequencing. HBV viraemia levels were significantly lower (P = 0.04) in patients with co-infection in comparison with single-infected HCC, whereas two different HBV viraemia profiles were detected in co-infection with or without circulating HCV. HBV genotype D was prevalent in the three groups and HCV genotype 1b was found to be the infecting strain in all patients. Lower variability in the pre-C/C region was found in co-infection in comparison with HBV single infection (P = 0.0004). A synonymous T1936C mutation was found in all co-infected HCC cases not related to the presence or absence of circulating HCV, and a hypermutated pre-C strain, characterized by the same mutational pattern, was identified in three HCC cases. The mutational pattern of the pre-C/C region was closely related to HBV replication efficiency, and specific HBV mutations selectively associated with HCV co-infection could be linked with accelerated HBV/HCV-related disease progression.

T1653 mutation in the box alpha increases the risk of hepatocellular carcinoma in patients with chronic hepatitis B virus genotype C infection

BACKGROUND

Most patients with chronic hepatitis B virus infection become carriers of inactive virus after hepatitis B e antigen seroconversion; however, a subgroup of patients have persistent abnormal transaminase levels and develop hepatocellular carcinoma after seroconversion.

METHODS

In an age-matched case-control study, 40 carriers of inactive virus (mean age+/-standard deviation [SD], 50.9 +/- 11.1 years), 40 patients with chronic hepatitis (mean age+/-SD, 50.2 +/- 8.9 years), and 40 patients with hepatocellular carcinoma (mean age+/-SD, 50.7 +/- 9.4 years) who were infected with hepatitis B virus genotype C and had test results positive for antibody to hepatitis B e antigen were analyzed.

RESULTS

The prevalence of T1653 in the box alpha was significantly higher among patients with hepatocellular carcinoma than among carriers of inactive virus who did not have hepatocellular carcinoma (70% vs. 25%; P < .0001) or chronic hepatitis (70% vs. 35%; P = .003). Mutations in the basic core promoter region (T1762/A1764) were frequently found in all groups, regardless of clinical status (in 77.5% of carriers of inactive virus, 77.5% of patients with chronic hepatitis, and 90% of patients with hepatocellular carcinoma). In the multivariate analysis, the presence of T1653, an alanine aminotransferase level of > or = 37 U/L, and a platelet count of < 18 x 10(4) platelets/mm3 were independent predictive values for hepatocellular carcinoma (odds ratio [95% confidence interval], 5.05 [1.56-16.35], 12.56 [3.05-51.77], and 11.5 [3.47-38.21], respectively). High alpha -fetoprotein level was the only independent predictive value for T1653 in patients with hepatocellular carcinoma (odds ratio, 12.67; 95% confidence interval, 1.19-134.17]). Among patients with test results positive for antibody to hepatitis B e antigen who had hepatocellular carcinoma and were infected with different genotypes of hepatitis B virus, the prevalence of T1653 was 40%, 15%, 25%, 25%, 67%, and 23% in patients infected with hepatitis B virus genotypes Aa, Ae, Ba, Bj, C, and D, respectively (P<.05 for genotype C vs. genotypes Ae, Ba, Bj, or D).

CONCLUSIONS

Our data indicate that the addition of T1653 mutation in the box alpha to the basic core promoter mutation increases the risk of hepatocellular carcinoma in patients with hepatitis B virus genotype C.

HBx M130K and V131I (T-A) mutations in HBV genotype F during a follow-up study in chronic carriers

BACKGROUND

Around 400 million people worldwide are chronically infected with Hepatitis B virus (HBV). An estimated 10% of these chronic patients develop progressive liver damage including cirrhosis and Hepatocellular Carcinoma (HCC). The HBx gene encodes a protein of 154 amino acids which is a transactivator and has been associated with HBV pathogenesis. A change in the amino acid sequences at positions 130 and 131 in the HBV-X protein (M130K and V131I) produced by T-A point mutations at the nucleic acids level has been associated with severe liver damage and HCC in patients from China and Africa. Further, such changes have been proposed as a prognostic marker for progressive liver damage and HCC. The purpose of this study was to determine if T-A mutations are present in HBV chronic carriers with genotype F (the major genotype in Costa Rica) and further, if these mutations are associated with HBV disease progression in Costa Rica HBV patients from 1972 to 1985.

RESULTS

Serum samples from 50 HBV positive individuals were amplified and directly sequenced, 48 belonged to genotype F, 1 from genotype D and another was classified as D or E. T-A mutations were absent in 17 acute patients who recovered, but was present in 12 of 29 chronic carrier samples (42.8%), in one sample the T-A mutations were detected as early as 29 days after clinical onset of disease. In 17 carriers with available liver biopsies, T-A mutations were found in 8 sera of 13 (61.5%) classified as moderate or severe, and none in 4 biopsies with mild liver damage. However, it was not possible to demonstrate a statistical association between the presence of T-A mutations and moderate/severe liver damage, using a Fischer exact test, 1 tail, p = 0.05. In 4 patients HCC was diagnosed, and 2 of them presented the T-A mutations in their sera.

CONCLUSION

T-A mutations were found in HBV genotype F in chronic carriers but not in patients who recovered from acute infection. These mutations could be developing early during infection although the possibility of infection with the mutant virus could not be excluded. More studies are necessary to establish if the T-A mutation can be used as a prognostic marker for severity of liver disease in patients infected with HBV.

Hepatitis B virus pre-S2 mutant upregulates cyclin A expression and induces nodular proliferation of hepatocytes

Naturally occurring mutants with a deletion in the pre-S2 region of the large surface protein (Delta S2-LHBs) are prevalent in serum and livers of patients with chronic hepatitis B virus (HBV) infection associated with cirrhosis. The Delta S2-LHBs protein is retained in the endoplasmic reticulum (ER) and may induce ER stress. One interesting observation is the consistently clustered distribution of hepatocytes expressing Delta S2-LHBs. In this study, complementary DNA microarray analysis identified cyclin A and several groups of genes as being significantly upregulated by Delta S2-LHBs in the HuH-7 cell line. This observation was confirmed in liver tissues. The induction of cyclin A expression may occur via the specific transactivator function of Delta S2-LHBs independent of ER stress. In the presence of Delta S2-LHBs, hepatocytes sustained cyclin A expression and cell cycle progression under ER stress and displayed increased BrdU incorporation with multinuclear formation. Furthermore, Delta S2-LHBs could enhance anchorage-independent cell growth in a nontransformed human hepatocyte line and induced nodular proliferation of hepatocytes in transgenic mice. In conclusion, these in vitro and in vivo data support a role for Delta S2-LHBs in the hepatocyte hyperplasia and a likely role in the process of HBV-related tumorigenesis.