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

The oncogenic role of hepatitis B virus X gene in hepatocarcinogenesis: recent updates

Hepatocellular carcinoma (HCC) is the most prevalent form of primary liver cancers with high mortality rate. Among its various etiological factors, one of the major risk factors for HCC is a chronic infection of hepatitis B virus (HBV). HBV X protein (HBx) has been identified to play an important role in the HBV-induced HCC pathogenesis since it may interfere with several key regulators of many cellular processes. HBx localization within the cells may be beneficial to HBx multiple functions at different phases of HBV infection and associated hepatocarcinogenesis. HBx as a regulatory protein modulates cellular transcription, molecular signal transduction, cell cycle, apoptosis, autophagy, protein degradation pathways, and host genetic stability via interaction with various factors, including its association with various non-coding RNAs. A better understanding on the regulatory mechanism of HBx on various characteristics of HCC would provide an overall picture of HBV-associated HCC. This article addresses recent data on HBx role in the HBV-associated hepatocarcinogenesis.

Distribution and Clinical Significance of Hepatitis B virus A1762T/G1764A Double Mutation in Chronic Hepatitis B Patients: A Cross-Sectional Study

BACKGROUND

Chronic hepatitis B (CHB) is well-known as a major risk for liver cirrhosis and hepatocellular carcinoma (HCC). The A1762T/G1764A double mutation in the hepatitis B virus genome affects the production of HBe antigen and is established as a predictive marker for progression to HCC. Thus, this study aimed to investigate the prevalence and clinical significance of the mutation in Thai CHB patients.

METHODS

 A cross-sectional study was conducted in 78 Thai CHB patients who were assessed for hepatitis B profiles, HBsAg, HBeAg and anti-HBeAg, transaminitis, liver fibrosis defined by FIB-4 (FIB-4) score and AST to platelet ratio index (APRI), alpha-fetoprotein (AFP) and active hepatitis B status. HBV A1762T/G1764A mutation was examined by SYBR Green I Real-time PCR. Chi-square and Mann-Whiney U tests were performed to determine the association between the mutation and variables.

RESULTS

The prevalence of patients infected with the A1762T/G1764A mutation was 44.9%. The mutation was associated with HBeAg status (p=0.027) and HBsAg levels (p=0.008), transaminitis (p=0.011), and active hepatitis B (p=0.037), but not liver fibrosis markers, FIB-4 score and APRI, and AFP. Binary logistic regression identified the mutation as a predictive factor of active hepatitis B (OR 3.5, 95%CI, 1.1-11.3, p=0.037). Patients infected with the mutant exhibited significantly higher levels of HBsAg (p=0.011) and HBV viral load (p=0.047), but lower levels of HBeAg (p=0.12) than those infected with the wild-type HBV.

CONCLUSION

The data indicate the high prevalence of the A1762T/G1764A mutation and its significant association with the severity of Thai CHB patients and the HBV mutation is proposed as a predictive marker of active hepatitis B status in CHB patients.

Detection of Immune Escape and Basal Core Promoter/Precore Gene Mutations in Hepatitis B Virus Isolated from Asymptomatic Hospital Attendees in Two Southwestern States in Nigeria

Several mutations in the surface (S), basal core promoter (BCP), and precore (PC) genes of the hepatitis B virus have been linked to inaccurate diagnosis and the development of immune escape mutants (IEMs) of the infection, which can lead to chronic infection. Understanding the prevalence and spread of these mutations is critical in the global effort to eliminate HBV. Blood samples were collected from 410 people in Osun and Ekiti states, southwest Nigeria, between 2019 and 2021. Participants were drawn from a group of asymptomatic people who were either blood donors, outpatients, or antenatal patients with no record of HBV infection at the medical outpatients' unit of the hospital. DNA was extracted from plasma using a Qiagen DNEasy kit, followed by nested PCR targeting HBV S and BCP/PC genes. The Sanger sequencing method was used to sequence the positive PCR amplicons, which were further analyzed for IEMs, BCP, and PC mutations. HBV-DNA was detected in 12.4% (51/410) of individuals. After DNA amplification and purification, 47.1% (24) of the S gene and 76.5% (39) of the BCP/PC gene amplicons were successfully sequenced. Phylogenetic analysis showed that all the HBV sequences obtained in this study were classified as HBV genotype E. Mutational analysis of the major hydrophilic region (MHR) and a-determinant domain of S gene sequences revealed the presence of three immune escape mutations: two samples harbored a T116N substitution, six samples had heterogenous D144A/N/S/H substitution, and one sample had a G145E substitution, respectively. The BCP/PC region analysis revealed a preponderance of major BCP mutants, with the prevalence of BCP double substitutions ranging from 38.5% (A1762T) to 43.6% (G1764A). Previously reported classical PC mutant variants were observed in high proportion, including G1896A (33.3%) and G1899A (12.8%) mutations. This study confirms the strong presence of HBV genotype E in Nigeria, the ongoing circulation of HBV IEMs, and a high prevalence of BCP/PC mutants in the cohorts. This has implications for diagnosis and vaccine efficacy for efficient management and control of HBV in the country.

A Narrative Review on the Specific Pattern of HBV Genotype in Bangladesh: Clinical Implications for Management

Background and aims

Bangladesh's unique epidemiological landscape presents an intriguing puzzle. This South Asian nation, with its complex sociodemographic and environmental factors, is home to a diverse array of hepatitis-B virus (HBV) genotypes, identified as Genotype C, with Genotypes D and A also making a significant contribution to the viral landscape. Reviewing such insights is necessary not only to underscore the country's regional diversity in HBV strains but also to bring into focus the clinical implications these genetic variations may have on disease progression and management.

Methods

A thorough database search covered various sources using relevant keywords like "Hepatitis B virus genotypes", "HBV genotypes in Bangladesh", and "HBV clinical implications". The review synthesized findings and analyzed HBV genotype prevalence and clinical implications in Bangladesh.

Results

Genotypes C and D collectively represent 82% of chronic hepatitis-B infection (CHB) cases in Bangladesh, underscoring their regional prevalence. The geographic context is pivotal in understanding HBV infection dynamics and disease progression in this area. Notably, genotype C and the presence of A1762T/G1764A mutations appear to have a distinct impact on disease development, potentially affecting the immune response in CHB patients. This highlights the need for tailored management approaches in this specific region. Further research is vital to confirm and elaborate on these findings, particularly in relation to how these mutations influence the host's immune response.

Conclusion and clinical significance

In summary, studies on HBV genotypes in Bangladesh stress the need for genotype-specific clinical considerations and more research to improve diagnostics and therapies.

How to cite this article

Raihan R, Akbar SMF. A Narrative Review on the Specific Pattern of HBV Genotype in Bangladesh: Clinical Implications for Management. Euroasian J Hepato-Gastroenterol 2023;13(2):152-158.

Decreased expression of HBV surface antigen (HBsAg) with sK122R and sV96A co-mutation is associated with an ineffective antibody response in a chronic hepatitis B patient

BACKGROUND

Emergence and predominance of hepatitis B virus (HBV) variants carrying S gene mutations frequently occur in HBV-infected individuals. Here, coexistent serum anti-HBsAg antibody (HBsAb) and HBV surface antigen (HBsAg) were detected in a chronic HBV patient. The patient's HBsAg proteins possessed amino acid substitutions sK122R and sV96A. We reported this case and conducted relevant studies to investigate differences in expression levels and antibody neutralization of HBsAg proteins bearing sK122R and sV96A amino acid substitutions to explore causes of antigen-antibody coexistence in a chronic hepatitis B patient.

STUDY DESIGN

We first sequenced the S gene from HBV present within the patient's serum. Based on the S gene sequence, we cloned wild-type and mutated S gene sequences via site-directed mutagenesis to construct expression plasmids pJW4303-WT (wild-type), pJW4303-sV96A, pJW4303-sK122R, and pJW4303-sV96A-sK122R. Plasmids were transfected into HEK 293 T cells then culture supernatants and cells were collected. Collected cells and supernatants were next subjected to a series of quantitative and functional tests to assess expression and neutralization characteristics of wild-type and mutant HBsAg proteins.

RESULTS

Based on quantification of HBsAg expression in cells transfected with the four plasmids, HBsAg-sK122R-sV96A was more intracellularly retained and less secreted than HBsAg-sV96A single-mutant protein and WT. Neutralization ability of serum from chronic HBV patient against culture supernatants containing recombinant HBsAg proteins were ranked from highest to lowest as HBsAg-sV96A, HBsAg-sV96A-sK122R, and HBsAg-sK122R. However, no significant differences of neutralization efficiency by high-potency antibodies from HBV-vaccinees against these three mutant proteins were observed.

CONCLUSIONS

The levels of HBsAg proteins with amino acid substitutions sV96A-sK122R were greatly reduced in culture supernatants but were apparently increased in the intracellular fraction. This may account for the higher levels of HBV replication in patients. HBsAg neutralization by HBsAb in this patient may have been compromised by the HBsAg sK122R amino acid substitution, suggesting that antibodies produced by the patient had lost their HBV-neutralizing effect.

Hepatitis B Virus-Associated Hepatocellular Carcinoma

Hepatitis B virus (HBV) is DNA-based virus, member of the Hepadnaviridae family, which can cause liver disease and increased risk of hepatocellular carcinoma (HCC) in infected individuals, replicating within the hepatocytes and interacting with several cellular proteins. Chronic hepatitis B can progressively lead to liver cirrhosis, which is an independent risk factor for HCC. Complications as liver decompensation or HCC impact the survival of HBV patients and concurrent HDV infection worsens the disease. The available data provide evidence that HBV infection is associated with the risk of developing HCC with or without an underlying liver cirrhosis, due to various direct and indirect mechanisms promoting hepatocarcinogenesis. The molecular profile of HBV-HCC is extensively and continuously under study, and it is the result of altered molecular pathways, which modify the microenvironment and lead to DNA damage. HBV produces the protein HBx, which has a central role in the oncogenetic process. Furthermore, the molecular profile of HBV-HCC was recently discerned from that of HDV-HCC, despite the obligatory dependence of HDV on HBV. Proper management of the underlying HBV-related liver disease is fundamental, including HCC surveillance, viral suppression, and application of adequate predictive models. When HBV-HCC occurs, liver function and HCC characteristics guide the physician among treatment strategies but always considering the viral etiology in the treatment choice.

Roles of APOBEC3 in hepatitis B virus (HBV) infection and hepatocarcinogenesis

APOBEC3 (A3) cytidine deaminases inhibit hepatitis B virus (HBV) infection and play vital roles in maintaining a variety of biochemical processes, including the regulation of protein expression and innate immunity. Emerging evidence indicates that the deaminated deoxycytidine biochemical activity of A3 proteins in single-stranded DNA makes them a double-edged sword. These enzymes can cause cellular genetic mutations at replication forks or within transcription bubbles, depending on the physiological state of the cell and the phase of the cell cycle. Under pathological conditions, aberrant expression of A3 genes with improper deaminase activity regulation may threaten genomic stability and eventually lead to cancer development. This review attempted to summarize the antiviral activities and underlying mechanisms of A3 editing enzymes in HBV infections. Moreover, the correlations between A3 genes and hepatocarcinogenesis were also elucidated.

Viral Hepatitis and Hepatocellular Carcinoma: State of the Art

Viral hepatitis is one of the main causes leading to hepatocellular carcinoma (HCC). The continued rise in incidence of HCC suggests additional factors following infection may be involved. This review examines recent studies investigating the molecular mechanisms of chronic hepatitis and its association with hepatocarcinogenesis. Hepatitis B virus patients with genotype C display an aggressive disease course leading to HCC more than other genotypes. Furthermore, hepatitis B excretory antigen (HBeAg) seems to be a more sensitive predictive tumor marker exhibiting a six-fold higher relative risk in patients with positive HBsAg and HBeAg than those with HBsAg only. Single or combined mutations of viral genome can predict HCC development in up to 80% of patients. Several mutations in HBx-gene are related with higher HCC incidence. Overexpression of the core protein in HCV leads to hepatocellular lipid accumulation associated with oncogenesis. Reduced number and decreased functionality of natural killer cells in chronic HCV individuals dysregulate their surveillance function in tumor and viral cells resulting in HCC. Furthermore, high T-cell immunoglobulin and mucin 3 levels supress CD8+ T-cells, which lead to immunological dysregulation. Hepatitis D promotes HCC development indirectly via modifications to innate immunity, epigenetic alterations and production of reactive oxygen species with the LHDAg being the most highly associated with HCC development. Summarizing the results, HBV and HCV infection represent the most associated forms of viral hepatitis causing HCC. Further studies are warranted to further improve the prediction of high-risk patients and development of targeted therapeutics preventing the transition from hepatic inflammation–fibrosis to cancer.

Blood-Based Biomarkers in Hepatitis B Virus-Related Hepatocellular Carcinoma, Including the Viral Genome and Glycosylated Proteins

Hepatitis B virus (HBV) infection is a major risk factor for hepatocellular carcinoma (HCC) development and is a global public health issue. High performance biomarkers can aid the early detection of HCC development in HBV-infected individuals. In addition, advances in the understanding of the pathogenesis of HBV infection and in clinical laboratory techniques have enabled the establishment of disease-specific tests, prediction of the progression of liver diseases, including HCC, and auxiliary diagnosis of HCC, using blood-based methods instead of biopsies of liver or HCC tissues. Viral factors such as the HBV genotype, HBV genetic mutations, HBV DNA, and HBV-related antigens, as well as host factors, such as tumor-associated proteins and post-translational modifications, especially glycosylated proteins, can be blood-based, disease-specific biomarkers for HCC development in HBV-infected patients. In this review, we describe the clinical applications of viral biomarkers, including the HBV genome and glycosylated proteins, for patients at a risk of HBV-related HCC, based on their molecular mechanisms. In addition, we introduce promising biomarker candidates for practical use, including colony stimulating factor 1 receptor (CSF1R), extracellular vesicles, and cell-free, circulating tumor DNA. The clinical use of such surrogate markers may lead to a better understanding of the risk of disease progression and early detection of HCC in HBV-infected patients, thereby improving their prognosis.

Prevalence of Dual-Positivity for Both Hepatitis B e Antigen and Hepatitis B e Antibody Among Hospitalized Patients with Chronic Hepatitis B Virus Infection

Objective

The detection of dual-positivity for both hepatitis B e antigen (HBeAg) and hepatitis B e antibody (anti-HBe) is not typically performed for patients with hepatitis B virus (HBV). This cross-sectional study was designed to figure out the prevalence of dual-positivity for both HBeAg and anti-HBe (DEP) among hospitalized patients with chronic hepatitis B virus infection (C-HBVI).

Patients and Methods

Data from 2820 cases with C-HBVI from two centers in China were retrospectively analyzed. Univariate and multivariate logistic regression analyses were undertaken to identify the risk factors for liver fibrosis (LF) and acute-on-chronic liver failure (ACLF).

Results

There were 165 (5.9%), 688, and 1903 patients in DEP, HBeAg+/anti-HBe-, and HBeAg-/anti-HBe+ groups, respectively. The DEP patients’ median age was 43.6 years old and 71.5% of them were male. They had higher levels of alanine transaminase, total bilirubin, and international normalized ratio. Furthermore, DEP cases had a higher proportion of liver cirrhosis, and it was associated with non-invasive testing of LF, including aspartate transaminase (AST)-to-platelet ratio index (APRI) >1.5 (odds ratio (OR) = 1.96, 95% confidence interval (CI): 1.27–3.03, P = 0.002) and fibrosis-4 (FIB-4) score >1.45 (OR = 2.07, 95% CI: 1.28–3.34, P = 0.003). DEP also contributed to the elevated risk of ACLF (OR = 4.80, 95% CI: 2.02–11.39, P < 0.001).

Conclusion

DEP cases are at higher risks of LF and ACLF than other patients with HBV infection. A fast diagnosis and an active monitoring of liver diseases for DEP patients are extremely vital.

Analysis of Hepatitis B Virus Genotype D in Greenland Suggests the Presence of a Novel Quasi-Subgenotype

A disproportionate number of Greenland's Inuit population are chronically infected with Hepatitis B virus (HBV; 5-10%). HBV genotypes B and D are most prevalent in the circumpolar Arctic. Here, we report 39 novel HBV/D sequences from individuals residing in southwestern Greenland. We performed phylodynamic analyses with ancient HBV DNA calibrators to investigate the origin and relationship of these taxa to other HBV sequences. We inferred a substitution rate of 1.4 × 10-5 [95% HPD 8.8 × 10-6, 2.0 × 10-5] and a time to the most recent common ancestor of 629 CE [95% HPD 37-1138 CE]. The Greenland taxa form a sister clade to HBV/D2 sequences, specifically New Caledonian and Indigenous Taiwanese sequences. The Greenland sequences share amino acid signatures with subgenotypes D1 and D2 and ~97% sequence identity. Our results suggest the classification of these novel sequences does not fit within the current nomenclature. Thus, we propose these taxa be considered a novel quasi-subgenotype.

Dynamic profile of the HBeAg-anti-HBe system in acute and chronic hepatitis B virus infection: A clinical-laboratory approach

Wild-type HBV infection is followed by the blood expression of its widely known serological markers of infection, and designated as, hepatitis B virus surface antigen (HBsAg) and its antibody (anti-HBs), anti-HBc antibodies (IgM/IgG), and hepatitis B virus 'e' antigen (HBeAg) and its antibody (anti-HBe). These markers are detected as the infection develops and its kinetic behavior serves as a basis for monitoring the disorder and for diagnosing the clinical form or infection phase. Among these, the HBeAg-anti-HBe system markers demonstrate a dynamic profile whose interpretation, both in the acute or chronic HBV infection context, can offer greater difficulty to the health professionals, due to its particularities. This review offers a revisit to the markers dynamics of this system in the acute and chronic HBV infection and to the clinical and laboratory significance of its expression in these two clinical contexts.

Hepatitis B Virus Oncoprotein HBx Is Not an ATPase

HBx is the smallest gene product of the Hepatitis B virus (HBV) and an oncogenic stimulus in chronic infections leading to liver disease. HBx interacts and interferes with numerous cellular processes, but its modes of action remain poorly understood. It has been invoked that HBx employs nucleotide hydrolysis to regulate molecular pathways or protein-protein interactions. In the present study, we reinvestigate the (d)NTP hydrolysis of recombinant HBx to explore its potential as a biochemical probe for antiviral studies. For our investigations, we employed existing soluble constructs (i.e., GST-HBx, MBP-HBx) and engineered new fusion proteins (i.e., DsbC-HBx, NusA-HBx), which are shown to serve as better systems for in vitro research. We performed mutational scanning of the computationally predicted NTP-binding domain, which includes residues associated with clinical cases. Steady-state and end-point activity assays, in tandem with mass-spectrometric analyses, reveal that the observed hydrolysis of all alleged HBx substrates, ATP, dATP, and GTP, is contingent on the presence of the GroEL chaperone, which preferentially copurifies as a contaminant with GST-HBx and MBP-HBx. Collectively, our findings provide new technical standards for recombinant HBx studies and reveal that nucleotide hydrolysis is not an operant mechanism by which HBx contributes to viral HBV carcinogenesis.

In silico Analysis of Genetic Diversity of Human Hepatitis B Virus in Southeast Asia, Australia and New Zealand

The extent of whole genome diversity amongst hepatitis B virus (HBV) genotypes is not well described. This study aimed to update the current distribution of HBV types and to investigate mutation rates and nucleotide diversity between genotypes in Southeast Asia, Australia and New Zealand. We retrieved 930 human HBV complete genomes from these regions from the NCBI nucleotide database for genotyping, detection of potential recombination, serotype prediction, mutation identification and comparative genome analyses. Overall, HBV genotypes B (44.1%) and C (46.2%) together with predicted serotypes adr (36%), adw2 (29%) and ayw1 (19.9%) were the most commonly circulating HBV types in the studied region. The three HBV variants identified most frequently were p.V5L, c.1896G>A and double mutation c.1762A>T/c.1764G>A, while genotypes B and C had the widest range of mutation types. The study also highlighted the distinct nucleotide diversity of HBV genotypes for whole genome and along the genome length. Therefore, this study provided a robust update to HBV currently circulating in Southeast Asia, Australia and New Zealand as well as an insight into the association of HBV genetic hypervariability and prevalence of well reported mutations.

Occult hepatitis B infection by a recombinant D/C virus in an immunosuppressed patient

Approximately 300 million people worldwide were living with chronic hepatitis B virus infection as of 2016, however, this number does not account for those who might be living with occult hepatitis B virus infection due to difficulty diagnosing this condition. The multiple genotypes and the ability of the hepatitis B virus to acquire mutations that down-regulate its expression make occult hepatitis B virus infection a very elusive diagnosis. This is especially worrisome when there is a need to start immunosuppressive therapies, since there is a risk of reactivation in undiagnosed patients. We present a case of female patient who was referred to the consultation because she was about to start chemotherapy with an anti-CD20 agent and had a positive anti-HBc and anti-HBs. During routine workup an occult hepatitis B virus infection was diagnosed. Upon further study mutations in the PreCore and Basal Core Promoter regions were identified, as well as, a double genotype D/C. Therapy with tenofovir was initiated before the patient was started on chemotherapy. This case highlights the importance of comprehensive studying of patients who present with apparently resolved chronic hepatitis B virus infection, especially when they are about to start immunosuppressive therapies.

High possibility of hepatocarcinogenesis in HBV genotype C1 infected Cambodians is indicated by 340 HBV C1 full-genomes analysis from GenBank

Approximately 75% of hepatocellular carcinomas (HCC) occur in Asia; core promoter mutations are associated with HCC in HBV genotype C, the dominant genotype in Cambodia. We analyzed these mutations in Cambodian residents and compared them with HBV full genomes registered in GenBank. We investigated the characteristics of 26 full-length HBV genomes among 35 residents positive for hepatitis B surface antigen in Siem Reap province, Cambodia. Genotype C1 was dominant (92.3%, 24/26), with one case of B2 and B4 each. Multiple mutations were confirmed in 24 Cambodian C1 isolates, especially double mutation at A1762T/G1764A in 18 isolates (75.0%), and combination mutation at C1653T and/or T1753V and A1762T/G1764A in 14 isolates (58.3%). In phylogenetic analysis, 16 of 24 isolates were located in the cluster with Laos, Thailand, and Malaysia. In 340 GenBank-registered C1 strains, 113 (33.2%) had combination mutation amongst which 16.5%, 34.2%, and 95.2% were found in ASC, chronic hepatitis, and liver cirrhosis (LC)/HCC respectively (P < 0. 001). Mutations were abundantly found in 24 Cambodian C1 isolates, and 340 C1 strains from GenBank showed mutation in genotype C1 brings high possibility of LC/HCC occurrence. Therefore, we suggest that Cambodian people infected with HBV genotype C1 have high possibility of hepatocarcinogenesis.

HBx-K130M/V131I Promotes Liver Cancer in Transgenic Mice via AKT/FOXO1 Signaling Pathway and Arachidonic Acid Metabolism

Chronic hepatitis B viral (HBV) infection remains a high underlying cause for hepatocellular carcinoma (HCC) worldwide, while the genetic mechanisms behind this remain unclear. This study elucidated the mechanisms contributing to tumor development induced by the HBV X (HBx) gene of predominantly Asian genotype B HBV and its common HBx variants. To compare the potential tumorigenic effects of K130M/V131I (Mut) and wild-type (WT) HBx on HCC, the Sleeping Beauty (SB) transposon system was used to deliver HBx Mut and WT into the livers of fumarylacetoacetate hydrolase (Fah)-deficient mice and in the context of transformation related protein 53 (Trp53) deficiency. From our results, HBx Mut had a stronger tumorigenic effect than its WT variant. Also, inflammation, necrosis, and fibrosis were evident in HBx experimental animals. Reduction of forkhead box O1 (FOXO1) with increased phosphorylation of upstream serine/threonine kinase (AKT) was detected under HBx Mut overexpression. Thus, it is proposed that HBx Mut enhances disease progression by reducing FOXO1 via phosphorylation of AKT. At the metabolomic level, HBx altered the expression of genes that participated in arachidonic acid (AA) metabolism, as a result of inflammation via accumulation of proinflammatory factors such as prostaglandins and leukotriene in liver. Taken together, the increased rate of HCC observed in chronic hepatitis B patients with K130M/V131I-mutated X protein, may be due to changes in AA metabolism and AKT/FOXO1 signaling. IMPLICATIONS: Our findings suggested that HBx-K130M/V131I-mutant variant promoted HCC progression by activating AKT/FOXO1 pathway and inducing stronger inflammation in liver via AA metabolism.

An Association Between Core Mutations in Hepatitis B Virus Genotype F1b and Hepatocellular Carcinoma in Alaskan Native People

Hepatitis B virus (HBV) genotype F1b infection is strongly associated with hepatocellular carcinoma (HCC) in young Alaskan Native (AN) people. However, the mechanisms by which genotype F1b causes HCC are unclear. Here, we analyzed the clinical and virological significance of genotype F1b in long-term serial samples from 20 HCC patients with HBV infection. Complete sequence analyses revealed that all isolates were genotype F1b. In the HCC patients, T1938C and A2051C mutations in the core region had accumulated significantly with A1762T/G1764A mutations in the basal core promoter (BCP) region and G1896A mutation in the precore (PC) region. Several HBV clones containing the core mutations were examined for their replication efficiency and core stability in vitro. Clones containing the A2051C mutation replicated more efficiently than the wild type in association with enhanced stability of core protein dimerization. In chimeric mice with human hepatocytes carrying BCP/PC/2051 mutant but not with wild-type virus, liver fibrosis was induced in association with high levels of serum HBV DNA and hepatitis B surface antigen. Interestingly, microarray analysis and validation study showed that five genes associated with cell proliferation or carcinogenesis, v-myc avian myelocytomatosis viral oncogene homolog, Grb2-associated binding protein 2, bradykinin receptor B2, follistatin, and mitogen-activated protein kinase kinase kinase 8, were significantly up-regulated in human hepatocytes infected with genotype F1b, particularly the BCP/PC/2051 mutant, compared with other genotypes. Conclusion: We have identified an association between Alaska-specific core mutations and HCC development in AN people infected with genotype F1b; accumulation of these core mutations during the course of chronic infection with genotype F1b would contribute to HCC development in AN people earlier in life.

New and Old Biomarkers for Diagnosis and Management of Chronic Hepatitis B Virus Infection

Tests to detect the presence and activity of hepatitis B virus (HBV) are the cornerstones of diagnosis and management. Assays that detect or measure serum levels of HB surface antigen, HB surface antibody, and HB core antibody are used to identify patients with exposure to HBV, whereas other tests provide information on the level of virus replication, presence of specific variants, and presence of virus reservoirs. Newer diagnostic tests, used only in research settings so far, aim to quantify levels of intrahepatic HBV replication. Other tests have been developed to detect HBV infection in resource-limited settings. We review point-of-care tests (essential in global screening efforts), standard diagnostic tests used in routine clinical management, and newer tests that might be used in clinical trials of agents designed to cure HBV infection.

Chronic hepatitis B virus infection

Chronic hepatitis B virus infection is a global public health threat that causes considerable liver-related morbidity and mortality. It is acquired at birth or later via person-to-person transmission. Vaccination effectively prevents infection and chronic hepatitis B virus carriage. In chronically infected patients, an elevated serum hepatitis B virus DNA concentration is the main risk factor for disease progression, although there are other clinical and viral parameters that influence disease outcomes. In addition to liver biochemistry, virological markers, and abdominal ultrasonography, non-invasive assessment of liver fibrosis is emerging as an important assessment modality. Long-term nucleos(t)ide-analogue therapy is safe and well tolerated, achieves potent viral suppression, and reduces the incidence of liver-related complications. However, a need to optimise management remains. Promising novel therapies are at the developmental stage. With current vaccines, therapies, and an emphasis on improving linkage to care, WHO's goal of eliminating hepatitis B virus as a global health threat by 2030 is achievable.

Host and Viral Genetic Variation in HBV-Related Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) is the fifth most common cancer in men and the second leading cause of cancer deaths globally. The high prevalence of HCC is due in part to the high prevalence of chronic HBV infection and the high mortality rate is due to the lack of biomarkers for early detection and limited treatment options for late stage HCC. The observed individual variance in development of HCC is attributable to differences in HBV genotype and mutations, host predisposing germline genetic variations, the acquisition of tumor-specific somatic mutations, as well as environmental factors. HBV genotype C and mutations in the preS, basic core promoter (BCP) or HBx regions are associated with an increased risk of HCC. Genome-wide association studies have identified common polymorphisms in KIF1B, HLA-DQ, STAT4, and GRIK1 with altered risk of HBV-related HCC. HBV integration into growth control genes (such as TERT), pro-oncogenic genes, or tumor suppressor genes and the oncogenic activity of truncated HBx promote hepatocarcinogenesis. Somatic mutations in the TERT promoter and classic cancer signaling pathways, including Wnt (CTNNB1), cell cycle regulation (TP53), and epigenetic modification (ARID2 and MLL4) are frequently detected in hepatic tumor tissues. The identification of HBV and host variation associated with tumor initiation and progression has clinical utility for improving early diagnosis and prognosis; whereas the identification of somatic mutations driving tumorigenesis hold promise to inform precision treatment for HCC patients.

BCP/PC mutation prevalence and their association with HBV replication in HIV/HBV co-infected patients

The high prevalence (14.3%) of HIV/HBV co-infections reported in west China makes it necessary to screen concurrent HBV infection in HIV carriers. HBV B genotype was shown to be dominant in 54 cases of HIV/HBV co-infection, accounting for 81.48% of the total. The total drug resistance rate observed was 3.70%. A1762T, G1764A and G1896A mutations were common mutations identified in the BCP/PC region. However, the prevalence of the G1896A mutation was significantly high among the HBeAg negative HIV/HBV co-infected patients, and may be associated with high HBV replication. Mutations in the PC region are related to the loss in synthesis of HBeAg and may accelerate HBV replication in HIV positive patients.

HBV subgenotypes F1b and F4 replication induces an incomplete autophagic process in hepatocytes: Role of BCP and preCore mutations

Hepatitis B virus (HBV) genotypes and mutants have been associated with differences in clinical and virological characteristics. Autophagy is a cellular process that degrades long-lived proteins and damaged organelles. Viruses have evolved mechanisms to alter this process to survive in host cells. In this work, we studied the modulation of autophagy by the replication of HBV subgenotypes F1b and F4, and the naturally occurring mutants BCP and preCore. HBV subgenotypes F1b and F4 replication induced accumulation of autophagosomes in hepatoma cells. However, no autophagic protein degradation was observed, indicating a blockage of autophagic flux at later stages. This inhibition of autophagy flux might be due to an impairment of lysosomal acidification in hepatoma cells. Moreover, HBV-mediated autophagy modulation was independent of the viral subgenotypes and enhanced in viruses with BCP and preCore naturally occurring mutations. These results contribute to understand the mechanisms by which different HBV variants contribute to the pathogenesis of HBV infections. In addition, this study is the first to describe the role that two highly prevalent naturally occurring mutations exert on the modulation of HBV-induced autophagy.

Occult Hepatitis B Virus Infection in Hyperlipidemia Patients

Chronic hepatitis B virus (HBV) infection is associated with lower prevalence of hyperlipidemia (HLP). However, occult HBV infection (OBI) in HLP patients has not yet been explored. OBI is defined as the presence of detectable HBV DNA in serum or liver tissue but undetectable HBV surface antigen in serum. In this study, 1,036 HLP patients and 1,134 replacement blood donor controls were recruited. Among them, 252 HLP patients and 255 blood donors with antibody to HBV core positive were selected and analyzed. HBV DNA was confirmed by nucleic acid testing assays, and nucleotide mutations were analyzed. OBI was detected in 9.5% (24/252) of HLP patients and 2.4% (6/255) of blood donors, respectively (P < 0.001). In HLP population, 41.7% of OBI and 13.6% of non-OBI carriers were associated with daily alcohol consuming > 30 g/day (P < 0.01), while in control population those rates were not statistically different between OBI and non-OBI carriers (P > 0.05). Viral load of OBI in HLP patients was higher than that of OBI in blood donors (P < 0.05), which was a positive correlation between total cholesterol and HBV viral load levels (r = 0.474 P = 0.019). HBV vaccination rate was found significantly lower in OBI HLP patients than that in non-OBI HLP patients (P < 0.01). Importantly, mutations were found in basic core promoter region of HBV among OBI HLP patients. In conclusion, the frequency of OBI is significantly higher in HLP patients, especially those patients with heavy daily alcohol consumption.

Patients with Coexistence of Circulating Hepatitis B Surface Antigen and Its Antibody May Have a Strong Predisposition to Virus Reactivation During Immunosuppressive Therapy: A Hypothesis

Hepatitis B virus (HBV) reactivation is a well-recognized complication in patients who undergo immunosuppressive drug therapy. Although the recommendation of antiviral prophylaxis made by the American Gastroenterological Association in 2015 focuses on the risk stratification of different immunosuppressive drugs, risk factors for HBV reactivation are also worth identifying in clinical practice. Recent studies have shown that the uncommon serological pattern of coexistent circulating HBV surface antigen (HBsAg) and its antibody (anti-HBs) was associated with double mutations (A1762T/G1764A) in the basal core promoter (BCP) region of the HBV genome, which is critical for HBV replication. Here, we depicted rheumatoid arthritis (RA) patients with coexistent HBsAg and anti-HBs in our medical center, who developed HBV reactivation during immunosuppressive drug therapy. DNA sequencing analysis of the HBV genome revealed triple mutations (A1762T, G1764A, and T1753V) in the BCP region, which could further enhance the ability of HBV replication. Hence, a novel hypothesis is advanced for the first time that patients with coexistent HBsAg and anti-HBs may have a strong predisposition to HBV reactivation due to specific BCP mutations. This hypothesis would, if correct, justify the concurrent detection of HBsAg and anti-HBs in HBV screening in patients with rheumatic diseases and quickly recognize patients with high risk of HBV reactivation. Further controlled studies are needed to confirm this hypothesis.

Associations between serum HBX quasispecies and their integration in hepatocellular carcinoma

HBV quasispecies are closely related to the course and outcome of liver disease. However, whether the complexity and diversity of HBX quasispecies affects its integration in the liver cell and thereby enhances the resultant carcinogenesis is still not clear. 15 HCC patients were recruited; genomic DNA and HBV DNA were extracted from liver cancer tissue and serum respectively. The integrated HBX fragment in liver cancer tissue was amplified by Alu repeat sequence-polymerase chain reaction (Alu-PCR) and sequenced. The serum HBX gene was amplified by nested PCR and sequenced. Quasispecies complexity and diversity, phylogenetic characteristics, lymphocyte count and survival time between HBX-integrated and HBX-unintegrated patients were evaluated. Results showed that the integrated HBX fragment was detected in the tumor tissue of nine patients, and the integration rate was 60.00% (9/15). Compared with the HBX-unintegrated patients, the HBX-integrated patients had a higher quasispecies complexity (P=0.028 and 0.004, at the nucleotide and amino acid levels, respectively). The HBX-integrated patients had a tendency of higher quasispecies diversity, lower lymphocyte count and the survival time. A total of 12 mutation sites were revealed in the HBX-integrated fragment after alignment with the reference sequence. In these, the HBX-integrated groups had significantly higher mutation frequencies at C1497T, A1630G, G1721A, A1762T/G1764A and A1774G. This study revealed influence factors of HBX integration both in virus and the host. The increased complexity and diversity of HBX quasispecies might destroy the host immune balance, and lead to HBX integration ultimately.

Contribution of C1485T mutation in the HBx gene to human and murine hepatocarcinogenesis

Although Hepatitis B virus (HBV) X gene mutations are frequently detected in HBV-related human hepatocellular carcinoma (HCC) patients, causative HBx mutations in the development of HCC have not yet been determined. We herein identified C1485T and C1653T mutations in the HBx gene as independent risk of HCC for HBV through the analysis using serum from chronic hepatitis B patients. We generated transgenic mice expressing wild-type (WT-HBxTg) and mutant (C1485T-HBxTg) HBx to assess the carcinogenic potential of mutated HBx. C1485T-HBxTg mice were more susceptible to diethylnitrosamine-induced hepatocarcinogenesis than WT-HBxTg mice and control non-Tg mice. The promotion of hepatocarcinogenesis in C1485T-HBxTg mice was accompanied by the activation of β-catenin and Jun N-terminal kinase (JNK) signaling pathways as well as the production of reactive oxygen species, whereas the activation of nuclear factor-kappa B in the livers of C1485T-HBxTg mice was attenuated. These results demonstrate that the HBx C1485T mutation contributes to human and murine hepatocarcinogenesis.

Basal core promoter and precore mutations among hepatitis B virus circulating in Brazil and its association with severe forms of hepatic diseases

BACKGROUND

In Brazil, few studies have investigated the prevalence of infection with the precore (PC) and basal core promoter (BCP) mutants of the hepatitis B virus (HBV).

OBJECTIVES

This study aimed to analyse the frequency of PC and BCP mutations among patients infected with HBV and to evaluate the association between the variants and advanced hepatic disease.

METHODS

A total of 161 patients infected with HBV were studied. To identify PC and BCP mutations, a 501-bp fragment of HBV DNA was amplified and sequenced.

FINDINGS

PC and BCP regions from HBV strains were successfully amplified and sequenced in 129 and 118 cases, respectively. PC and BCP mutations were detected in 61.0% and 80.6% of the cases, respectively. The A1762T/G1764A variant was identified in 36.7% of the patients with grade 1 and 2 liver fibrosis (29/79) and in 81.8% of the patients with grade 3 and 4 liver fibrosis (9/11) (p < 0.01); in 76.9% of the patients with cirrhosis (10/13) and in 38.1% of the patients without cirrhosis (40/105) (p = 0.01); and in 77.8% of the patients with hepatocellular carcinoma (HCC) (7/9) and in 39.4% of the patients without HCC (43/109) (p = 0.03).

MAIN CONCLUSIONS

A high prevalence of HBV PC and BCP mutants was found. The A1762T/G1764A variant was independently associated with advanced forms of liver fibrosis, hepatic cirrhosis, and HCC.

HLA-DQ gene polymorphisms are associated with hepatocellular carcinoma and hepatitis B surface antigen in chronic hepatitis B virus infection

AIM

Genome-wide association studies have revealed that single nucleotide polymorphism (SNP) of human leukocyte antigen (HLA)-DQ is associated with the clearance of hepatitis B surface antigen (HBsAg) in acute hepatitis B virus (HBV) infection. We examined the effects of SNPs on the development of hepatocellular carcinoma (HCC) and markers of HBV in chronic HBV infection.

METHODS

The SNPs of HLA-DQ (rs2856718 and rs7453920) were determined in 299 patients with chronic HBV infection.

RESULTS

In 224 hepatitis B e antigen (HBeAg)-negative patients, those with rs2856718 genotype AG + GG had significantly lower hepatitis B core-related antigen levels (P = 0.0184), less frequent treatment with nucleotide/nucleoside analogs (NAs) (P = 0.0433), and less frequent HCC development (P = 0.0256) than those with genotype AA. Multivariate analysis selected age (P = 0.0460), platelet count (P = 0.0481), γ-glutamyl transpeptidase (P = 0.0030), and nucleotide/nucleoside analog treatment (P = 0.0003) as factors independently associated with HCC development. HBeAg-negative patients with rs7453920 genotype GG had significantly lower HBsAg levels (P < 0.0001), a higher prevalence of HBV genotype C (P = 0.0063), and a lower prevalence of the wild-type basal core promoter region (P = 0.0045) than those with genotype AA + AG. Multivariate analysis selected age (P < 0.0001), platelet count (P = 0.0021), HBV DNA levels (P = 0.0314), wild type of precore region (P = 0.0015), and rs7453920 (P < 0.0001) as factors independently associated with HBsAg levels.

CONCLUSION

This study revealed an association between rs2856718 and HCC development and an association between rs7453920 and HBsAg levels.

X region mutations of hepatitis B virus related to clinical severity

Chronic hepatitis B virus (HBV) infection remains a major health problem, with more than 240 million people chronically infected worldwide and potentially 650000 deaths per year due to advanced liver diseases including liver cirrhosis and hepatocellular carcinoma (HCC). HBV-X protein (HBx) contributes to the biology and pathogenesis of HBV via stimulating virus replication or altering host gene expression related to HCC. The HBV X region contains only 465 bp encoding the 16.5 kDa HBx protein, which also contains several critical cis-elements such as enhancer II, the core promoter and the microRNA-binding region. Thus, mutations in this region may affect not only the HBx open reading frame but also the overlapped cis-elements. Recently, several types of HBx mutations significantly associated with clinical severity have been described, although the functional mechanism in most of these cases remains unsolved. This review article will mainly focus on the HBx mutations proven to be significantly related to clinical severity via epidemiological studies.