Metabonomic analysis of hepatitis B virus-induced liver failure:identification of potential diagnostic biomarkers by fuzzy support vector machine

Hepatitis B virus （HBV）-induced liver failure is an emergent liver disease leading to high mortality. The severity of liver failure may be reflected by the profile of some metabolites. This study assessed the potential of using metabolites as biomarkers for liver failure by identifying metabolites with good discriminative performance for its phenotype. The serum samples from 24 HBV-indueed liver failure patients and 23 healthy volunteers were collected and analyzed by gas chromatography-mass spectrometry （GC-MS） to generate metabolite profiles. The 24 patients were further grouped into two classes according to the severity of liver failure. Twenty-five eommensal peaks in all metabolite profiles were extracted, and the relative area values of these peaks were used as features for each sample. Three algorithms, F-test, k-nearest neighbor （KNN） and fuzzy support vector machine （FSVM） combined with exhaustive search （ES）, were employed to identify a subset of metabolites （biomarkers） that best predict liver failure. Based on the achieved experimental dataset, 93.62% predictive accuracy by 6 features was selected with FSVM-ES and three key metabolites, glyeerie acid, cis-aeonitie acid and citric acid, are identified as potential diagnostic biomarkers.

Treatment of hepatitis B virus-associated glomerulonephritis:A meta-analysis

AIM:To evaluate the efficacy of antiviral or corticosteroid treatment on hepatitis B virus-associated glomerulonephritis(HBV-GN) . METHODS:Six and five trials were used respectively to evaluate the efficacy of either antiviral or corticosteroid treatment on HBV-GN.Pediatric patients were pooled separately to assess their response to the above treatment modalities.The primary and secondary outcomes were remission of proteinuria and clearance of Hepatitis B e-antigen(HBeAg) ,respectively.A fixed or random effect model was established to collect the data. RESULTS:The remission rate of proteinuria(RR=1.69,95%CI:1.08-2.65) and the clearance rate of HBeAg(RR =6.44,95%CI:3.11-13.35) were significantly higher in antiviral treatment group than in control group.The proteinuria remission was significantly associated with HBeAg clearance(P=0.002) .However,the difference in proteinuria remission rate was not statistically significant between corticosteroid treatment group and controlgroup(RR=1.45,95%CI:0.68-3.11) .Antiviral therapy could significantly promote the HBeAg clearance in pediatric patients,but neither antiviral nor corticosteroid therapy could significantly decrease proteinuria in pediatric patients compared to controls. CONCLUSION:Antiviral but not corticosteroid treatment can decrease proteinuria and promote HBeAg clearance in HBV-GN patients.

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=l.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 AI762T/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.

Development of Fok-I based nested polymerase chain reaction-restriction fragment length polymorphism analysis for detection of hepatitis B virus X region V5M mutation

AIM: To develop a Fok-I nested polymerase chain reaction(PCR)-restriction fragment length polymorphism analysis(PRA) method for the detection of hepatitis B virus X region(HBx) V5 M mutation.METHODS: Nested PCR was applied into DNAs from 198 chronic patients at 2 different stages [121 patients with hepatocellular carcinoma(HCC) and 77 carrier patients]. To identify V5 M mutants, digestion of nested PCR amplicons by the restriction enzyme Fok-I(GGA TGN9↓) was done. For size comparison, the enzymetreated products were analyzed by electrophoresis on 2.5% agarose gels, stained with ethidium bromide, and visualized on a UV transilluminator.RESULTS: The assay enabled the identification of 69 patients(sensitivity of 34.8%; 46 HCC patients and 23 carrier patients). Our data also showed that V5 M prevalence in HCC patients was significantly higher than in carrier patients(47.8%, 22/46 patients vs 0%, 0/23 patients, P < 0.001), suggesting that HBx Ag V5 M mutation may play a pivotal role in HCC generation in chronic patients with genotype C infections.CONCLUSION: The Fok-I nested PRA developed in this study is a reliable and cost-effective method to detect HBx Ag V5 M mutation in chronic patients with genotype C2 infection.

Associations of IFN-γ rs2430561 T/A,IL28B rs12979860 C/T and ERα rs2077647 T/C polymorphisms with outcomes of hepatitis B virus infection:a meta-analysis

Several studies investigated associations of IFN-γ rs2430561 T/A,IL28 B rs12979860 C/T and ERα rs2077647 T/C gene polymorphisms with outcomes of hepatitis B virus（HBV） infection,but the results were controversial.Therefore,we performed a meta-analysis of all published observational studies to address this inconsistency.Literature was searched in online database and a systematic review was conducted based on the search results.A total of 24 studies were included and dichotomous data were presented as odds ratio（OR） with a 95%confidence interval（CI）.The rs2430561 T allele was associated with reduced persistent HBV infection risk（T vs.A：OR,0.690;95%CI,[0.490,0.971]）,while the rs2077647 T allele significantly increased the risk of persistent HBV infection（T vs.C：OR.1.678;95%CI,[1.212,2.3231）.Rs 2077647 CC might play a role in protecting individuals against HBV persistence（TT vs.CC：OR,4.109;95%CI,[2.609,6.473]）.Furthermore,carriers of the rs2430561 TT genotype were more likely to clear HBV spontaneously compared with those of the AA genotype（TT vs.AA：OR,0.555;95%CI,[0.359,0.856]）.For rs12979860 C/T polymorphism,no significant correlation with HBV infection outcomes was found.In subgroup analyses,the results were similar to those of overall analysis.However,for rs2077647 TT vs.TC＋CC,significantly increased risks were observed in the Asian and hospital-based population,but not in the overall analysis.IFN-γrs2430561 T/A and ERα rs2077647 T/C genetic polymorphisms were associated with outcomes of HBV infection,but no association was found between IL28 B rs12979860 C/T and HBV infection.

Risk factors for hepatocellular carcinoma in cirrhosis:A comprehensive analysis from a decade-long study

BACKGROUND Cirrhosis is a significant risk factor for the development of hepatocellular carcinoma(HCC).Variability in HCC risk among patients with cirrhosis is notable,particularly when considering the diverse etiologies of cirrhosis.AIM To identify specific risk factors contributing to HCC development in patients with cirrhosis.METHODS This retrospective study analyzed data from cirrhotic patients at Beijing Youan Hospital from January 1,2012 to September 30,2022 with at least 6 mo of followup.Patient demographics,medical histories,etiologies,and clinical characteristics were examined.Cox regression analysis was used to analyze correlations of the above parameters with hepatocarcinogenesis,while competing risk regression was used to estimate their adjusted hazard ratios accounting for death.The cumulative incidence was plotted over time.RESULTS Overall,5417 patients with cirrhosis(median age:54 years;65.8%males)were analyzed.Hepatitis B virus(HBV)was the most common etiology(23.3%),with 25%(n=1352)developing HCC over a 2.9-year follow-up period.Patients with multiple etiologies had the HCC highest incidence(30.3%),followed by those with HBV-related cirrhosis(29.5%).Significant risk factors included male sex,advanced age,hepatitis C virus(HCV)infection,elevated blood ammonia,and low platelet count.Men had a higher 5-year HCC risk than women(37.0%vs 31.5%).HBV,HCV,and HBV/HCV co-infected patients had 5-year risks of HCC of 45.8%,42.9%,and 48.1%,respectively,compared to 29.5%in nonviral hepatitis cases,highlighting the significant HCC risk from viral hepatitis,especially HBV,and underscores the importance of monitoring these high-risk groups.CONCLUSION In conclusion,HBV-related cirrhosis strongly correlates with HCC,with male sex,older age,viral hepatitis,elevated blood ammonia,and lower albumin and platelet levels increasing the risk of HCC.

Association of core promoter mutations of hepatitis B virus and viral load is different in HBeAg(+) and HBeAg(-) patients

AIM:To identify the prevalence of hepatitis B e antigen (HBeAg) and to assess the association of hepatitis B virus (HBV) core promoter mutations and viral load in Indonesian patients.METHODS:Sixty-four patients with chronic hepatitis,65 with liver cirrhosis and 50 with hepatocellular carcinoma were included in this study.HBeAg and hepatitis B e antibody (HBeAb) tests were performed using enzyme-linked immunosorbent assay and the mutations were analyzed by sequencing.Viral load was measured by real-time polymerase chain reaction.RESULTS:Of 179 patients,108 (60.3%) were HBeAg(-) and 86 (79.6%) of these HBeAg(-) patients had been seroconverted.The A1896 mutation was not found in HBeAg(+) patients,however,this mutation was detected in 70.7% of HBeAg(-) patients.This mutation was frequently found when HBeAg was not expressed (87.7%),compared to that found in HBeAg seroconverted patients (65.1%).The A1899 mutation was also more prevalent in HBeAg(-) than in HBeAg(+) patients (P=0.004).The T1762/A1764 mutation was frequently found in both HBeAg(+) and HBeAg(-) patients,however,the prevalence of this mutation did not significantly differ among the two groups (P=0.054).In HBeAg(+) patients,the T1762/A1764 mutation was correlated with lower HBV DNA (P < 0.001).The A1899 mutation did not correlate with HBV DNA (P=0.609).In HBeAg(-) patients,the T1762/A1764 mutation alone was not correlated with HBV DNA (P=0.095),however,the presence of either the T1762/A1764 or A1896 mutations was associated with increased HBV DNA (P < 0.001).CONCLUSION:The percentage of HBeAg(-) patients is high in Indonesia,and most of the HBeAg(-) patients had been seroconverted.The A1896 mutation was most likely the major cause of HBeAg loss.The T1762/A1764 mutation alone was associated with lower viral loads in HBeAg(+) patients,but not in HBeAg(-) patients.

Hepatitis B virus infection and hepatocellular carcinoma in sub- Saharan Africa: Implications for elimination of viral hepatitis by 2030?

Elimination of viral hepatitis in sub-Saharan Africa by 2030 is an ambitious feat.However,as stated by the World Health Organization,there are unprecedented opportunities to act and make significant contributions to the elimination target.With 60 million people chronically infected with hepatitis B virus(HBV)of whom 38800 are at risk of developing highly fatal hepatocellular carcinoma(HCC)every year,sub-Saharan Africa faces one of the greatest battles towards elimination of viral hepatitis.There is a need to examine progress in controlling the disproportionate burden of HBV-associated HCC in sub-Saharan Africa within the context of this elimination target.By scaling-up coverage of hepatitis B birth dose and early childhood vaccination,we can significantly reduce new cases of HCC by as much as 50%within the next three to five decades.Given the substantial reservoir of chronic HBV carriers however,projections show that HCC incidence and mortality rates in sub-Saharan Africa will double by 2040.This warrants urgent public health attention.The trends in the burden of HCC over the next two decades,will be determined to a large extent by progress in achieving early diagnosis and appropriate linkage to care for high-risk chronic HBV infected persons.

Hepatitis B reactivation in patients receiving direct-acting antiviral therapy or interferon-based therapy for hepatitis C:A systematic review and meta-analysis

AIM To assess the incidence of hepatitis B virus(HBV) reactivation in patients receiving direct-acting antiviral agent(DAA)-based therapy or interferon(IFN)-based therapy for hepatitis C and the effectiveness of preemptive antiHBV therapy for preventing HBV reactivation.METHODS The Pub Med, MEDLINE and EMBASE databases were searched, and 39 studies that reported HBV reactivation in HBV/hepatitis C virus coinfected patients receiving DAAbased therapy or IFN-based therapy were included. The primary outcome was the rate of HBV reactivation. The secondary outcomes included HBV reactivation-related hepatitis and the effectiveness of preemptive anti-HBV treatment with nucleos(t)ide analogues. The pooled effects were assessed using a random effects model. RESULTS The rate of HBV reactivation was 21.1% in hepatitis Bsurface antigen(HBs Ag)-positive patients receiving DAAbased therapy and 11.9% in those receiving IFN-based therapy. The incidence of hepatitis was lower in HBs Agpositive patients with undetectable HBV DNA compared to patients with detectable HBV DNA receiving DAA therapy(RR = 0.20, 95%CI: 0.06-0.64, P = 0.007). The pooled HBV reactivation rate in patients with previous HBV infection was 0.6% for those receiving DAA-based therapy and 0 for those receiving IFN-based therapy, and none of the patients experienced a hepatitis flare related to HBV reactivation. Preemptive anti-HBV treatment significantly reduced the potential risk of HBV reactivation in HBs Agpositive patients undergoing DAA-based therapy(RR = 0.31, 95%CI: 0.1-0.96, P = 0.042).CONCLUSION The rate of HBV reactivation and hepatitis flare occurrence is higher in HBs Ag-positive patients receiving DAA-based therapy than in those receiving IFN-based therapy, but these events occur less frequently in patients with previous HBV infection. Preemptive anti-HBV treatment is effective in preventing HBV reactivation.

Chronic hepatitis virus infection increases the risk of pancreatic cancer: a meta-analysis

BACKGROUND:Several reports have inconsistently demonstrated that there is an association between hepatitis B virus(HBV)or hepatitis C virus(HCV)infections and pancreatic cancer(PC).The aim of the present meta-analysis is to assess this possible relationship.DATA SOURCES:Studies were identified by searching available database from January 2000 to July 2012.Possible associations between PC risk and hepatitis B surface antigen(HBsAg)and its antibody(HBsAb),hepatitis B e antigen(HBeAg)and its antibody(HBeAb),anti-HBcAg antibody(HBcAb),and HCV antibody(anti-HCV)were evaluated.RESULTS:Eight case-control and two cohort studies were included,and their quality scores were assessed by the modified Newcastle-Ottawa Quality Assessment Scale(NOS).We found that HBsAg and anti-HCV seropositivity significantly increased risk of PC(OR=1.28,95%CI:1.11-1.48 and OR=1.21,95%CI:1.02-1.44).The presence of HBsAb was associated with a statistically significant decrease in the risk of PC(OR=0.40,95%CI:0.20-0.79)and HBeAb(OR=0.62,95%CI:0.39-0.99).HBsAg–/HBcAb+/HBsAb–or HBsAg–/HBcAb+/HBsAb+profile was not related to PC risk(OR=1.57,95%CI:0.83-2.98 and OR=1.24,95%CI:0.72-2.14).CONCLUSIONS:HBV/HCV infection increases the risk of PC.HBsAb and HBeAb seropositivity may be the protective factors against PC.It is still uncertain whether serological pattern of past exposure to HBV with or without natural immunity is associated with an enhanced probability of this malignancy.

Correlation between expression of HLA class Ⅱ antigen on hepatocyte membrane and viral replication in chronic hepatitis B virus carriers

In order to study the relationship between replicative status and human leucocyte antigens(HLA),HLA class Ⅱ antigen on hepatocyte membrane was analyzed in liver biopsies from 49 pa-tients with chronic hepatitis B virus infection.The results revealed that expression of HLA classⅡ antigen on hepatocyte membrane was observed in 57% (13/23) of hepatitis B e antigen (HBeAg)positive,only in 15% (4/26) of anti-HBe positive carriers.The display of HLA class Ⅱ antigen onhepatocyte membrane yeas found in 65% (11/17) hepatitis B core antigen (HBcAg) positive and in19% (6/32) HBcAg negative patients with chronic hepatitis B virus infection.There was nosignificant difference in the expression of HLA class Ⅱ antigen on hepatocyte membrane between mi-nor hepatic diseases and active liver diseases.These findings suggested that display of HLA classⅡ antigen on hepatocyte membrane might be associated with viral replication in the chronic hepati-tis B virus carriers.

Early viral kinetics during hepatitis C virus genotype 6 treatment according to IL28B polymorphisms

AIM: To investigate the early viral kinetics and interleukin-28B (IL28B) polymorphisms of hepatitis C genotype 6 during pegylated interferon and ribavirin therapy.

Preliminary study on the production of transgenic mice harboring hepatitis B virus X gene

AIM To establish transgenic mice lineage xharboring hepatitis B virus X gene and to provide an efficient animal model for studying the exact role of the HBx gene in the process of hepatocarcinogenesis. METHODS The HBx transgenic mice were produced by microinjecting the construct with X gene of HBV (subtype adr) DNA fragment into fertilized eggs derived from inbred C57 BL/6 strain; transgenic mice were identified by using Nested PCR; expression and phenotype of HBx gene were analyzed in liver from transgenic mice at the age of 8 weeks by RT PCR, pathologic examination and periodic acid schiff staining (PAS), respectively. RESULTS Five hundred and fourteen fertilized eggs of C57 BL/6 mice were microinjected with recombinant retroviral DNA fragment, and 368 survival eggs injected were transferred to the oviducts of 18 pseudopregnant recipient mice, 8 of them became pregnant and gave birth to 20 F1 offspring. Of 20 offsprings, four males and two females carried the hybrid gene (HBx gene). Four male mice were determined as founder, named X1, X5, X9 and X15. These founders were back crossed to set up F1 generations with other inbred C57BL/6 mice or transgenic littermates, respectively. Transmission of HBx gene in F1 offspring of X1, X5 and X9 except in X15 followed Mendelian rules. The expression of HBx mRNA was detected in liver of F1 offspring from the founder mice (X1 and X9), which showed vacuolation lesion and glycogen positive foci. CONCLUSION Transgenic mice harboring HBx gene were preliminarily established.

Hepatitis B virus pathogenesis: Fresh insights into hepatitis B virus RNA

Hepatitis B virus(HBV) is still a worldwide health concern. While divergent factors are involved in its pathogenesis, it is now clear that HBV RNAs, principally templates for viral proteins and viral DNAs, have diverse biological functions involved in HBV pathogenesis. These functions include viral replication, hepatic fibrosis and hepatocarcinogenesis. Depending on the sequence similarities, HBV RNAs may act as sponges for host mi RNAs and may deregulate mi RNA functions, possibly leading to pathological consequences. Some parts of the HBV RNA molecule may function as viralderived mi RNA, which regulates viral replication. HBV DNA can integrate into the host genomic DNA and produce novel viral-host fusion RNA, which may have pathological functions. To date, elimination of HBVderived covalently closed circular DNA has not been achieved. However, RNA transcription silencing may be an alternative practical approach to treat HBVinduced pathogenesis. A full understanding of HBV RNA transcription and the biological functions of HBV RNA may open a new avenue for the development of novel HBV therapeutics.

Factors predicting occurrence and prognosis of hepatitis-B-virus-related hepatocellular carcinoma

Primary liver cancer is an important cause of cancer death, and hepatocellular carcinoma （HCC） accounts for 70%-85% of total liver cancer worldwide. Chronic hepatitis B virus （HBV） infection contributes to 〉 75% of HCC cases. High serum viral load is the most reliable indicator of viral replication in predicting development of HCC. HBV genotype C is closely associated with HCC in cirrhotic patients aged 〉 50 years, whereas genotype B is associated with development of HCC in non-cirrhotic young patients and postoperative relapse of HCC. Different HBV subgenotypes have distinct patterns of mutations, which are clearly associated with increased risk of HCC. Mutations accumulate during chronic HBV infection and predict occurrence of HCC. Chronic inflammation leads to increased frequency of viral mutation via cellular cytidine deaminase induction. Mutations are negatively selected by host immunity, whereas some immuno-escaped HBV mutants are active in hepatocarcinogenesis. Inflammatory pathways contribute to the inflammation-necrosis-regeneration process, ultimately HCC. Their hallmark molecules can predict malignancy in HBV-infected subjects. Continuing inflammation is involved in hepatocarcinogenesis and closely related to recurrence and metastasis. HBV load, genotype C, viral mutations and expression of inflammatory molecules in HBV-related HCC tissues are significantly associated with poor prognosis. Imbalance between intratumoral CD8^＋T cells and regulatory T cells or Thl and Th2 cytokines in peritumoral tissues can predict prognosis of HBV-related HCC. These factors are important for developing active prevention and surveillance of HBV-infected subjects who are more likely to develop HCC, or for tailoring suitable treatment to improve survival or postpone postoperative recurrence of HCC.

Hepatitis B virus genotypes:Global distribution and clinical importance

At least 600000 individuals worldwide annually die of hepatitis B virus(HBV)-related diseases,such as chronic hepatitis B(CHB),liver cirrhosis(LC),and hepatocellular carcinoma(HCC).Many viral factors,such as viral load,genotype,and specific viral mutations,are known to affect disease progression.HBV reverse transcriptase does not have a proofreading function,therefore,many HBV genotypes,sub-genotypes,mutants,and recombinants emerge.Differences between genotypes in response to antiviral treatment have been determined.To date,10 HBV genotypes,scattered across different geographical regions,have been identified.For example,genotype A has a tendency for chronicity,whereas viral mutations are frequently encountered in genotype C.Both chronicity and mutation frequency are common in genotype D.LC and progression to HCC are more commonly encountered with genotypes C and D than the other genotypes.Pathogenic differences between HBV genotypes explain disease intensity,progression to LC,and HCC.In conclusion,genotype determination in CHB infection is important in estimating disease progression and planning optimal antiviral treatment.

High level of hepatitis B virus DNA after HBeAg-to-anti-HBe seroconversion is related to coexistence of mutations in its precore and basal core promoter

AIM: G1896A mutation in precore or A1762T/G1764Amutations in basal core promoter are suspected to be responsible for patients with detectable level of HBV DNA in serum after seroconversion from HBeAg to anti-Hbe. However, G1896A variant has impaired, while A1762T/ G1764A variant may have intact replication ability. They themselves or their coexistence status may play different roles in such meaningless seroconversion. For these reasons, the significances of these two types of mutations were comparatively investigated in this study. METHODS: One hundred and sixty-five sera with positive anti-Hbe and HBV DNA were collected from different patients. Mutations of G1896A and A1762T/G1764A among these serum samples were detected using competitively differentiated PCR. HBV DNA was demonstrated using real-time quantitative PCR. RESULTS: G1896A and/or A1762T/G1764A mutations were detected in 89.1% (147/165) out of patients with detectable HBV DNA in serum after HBeAg-to-anti-Hbe seroconversion. The positive rate of G1896A variants was significantly higher than that of A1762T/G1764A mutations (77.6% vs 50.3%, X2 = 26.61, P＜0.01). The coexistence positive rate of these two types of mutations was 38.8% (64/165). Coexistence mutations were found in 77.1% (64/83) out of sera with A1762T/G1764A mutations, and in 50.0% (64/128) out of sera with G1896A mutation. Compared with variants with G1896A mutation only, the coexistence mutations were predominant in patients with high level of serum HBV DNA, and related to higher total bilirubin, lower serum albumin and progressive liver diseases. CONCLUSION: The coexistence of G1896A mutation and A1762T/G1764A mutations is very common, and responsible for the major cases with high level of HBV DNA in serum and progressive liver diseases after HBeAg-to-anti-Hbe seroconversion. This coexistence mutation variant may have higher pathogenicity and replication ability.

Quasispecies structure,cornerstone of hepatitis B virus infection: Mass sequencing approach

Hepatitis B virus(HBV)is a DNA virus with complex replication,and high replication and mutation rates,leading to a heterogeneous viral population.The population is comprised of genomes that are closely related,but not identical;hence,HBV is considered a viral quasispecies.Quasispecies variability may be somewhat limited by the high degree of overlapping between the HBV coding regions,which is especially important in the P and S gene overlapping regions,but is less significant in the X and preCore/Core genes.Despite this restriction,several clinically and pathologically relevant variants have been characterized along the viral genome.Next-generation sequencing(NGS)approaches enable high-throughput analysis of thousands of clonally amplified regions and are powerful tools for characterizing genetic diversity in viral strains.In the present review,we update the information regarding HBV variability and present a summary of the various NGS approaches available for research in this virus.In addition,we provide an analysis of the clinical implications of HBV variants and their study by NGS.

Autophagy and microRNA in hepatitis B virus-relatedhepatocellular carcinoma

Approximately 350 million people worldwide are chronically infected by hepatitis B virus(HBV).HBV causes severe liver diseases including cirrhosis and hepatocellular carcinoma(HCC).In about 25%of affected patients,HBV infection proceeds to HCC.Therefore,the mechanisms by which HBV affects the host cell to promote viral replication and its pathogenesis have been the subject of intensive research efforts.Emerging evidence indicates that both autophagy and micro RNAs(mi RNAs)are involved in HBV replication and HBV-related hepatocarcinogenesis.In this review,we summarize how HBV induces autophagy,the role of autophagy in HBV infection,and HBV-related tumorigenesis.We further discuss the emerging roles of mi RNAs in HBV infection and how HBV affects mi RNAs biogenesis.The accumulating knowledge pertaining to autophagy and mi RNAs in HBV replication and its pathogenesis may lead to the development of novel strategies against HBV infection and HBV-related HCC tumorigenesis.