X gene mutations in hepatitis B patients with cirrhosis, with and without hepatocellular carcinoma

Hepatitis B virus X gene mutants emerge during antiviral therapy and increase cccDNA levels to compensate for replication suppression

BACKGROUND

Hepatitis B virus (HBV) X gene (HBx) mutants can develop during the natural course of chronic HBV infection. However, little is known about whether the emergence of HBx mutants during long-term antiviral therapy is an adaptation of HBV to antiviral stress. This study was to identify HBx mutants that emerged in patients experiencing Lamivudine resistance or suboptimal treatment.

METHODS

Forty-six Lamivudine-resistant patients and 46 patients with suboptimal treatment responses to Entecavir were enrolled in this study. HBx mutants were identified by sequence analysis and their roles in the HBV replication cycle were characterized.

RESULTS

We show that deletion/truncation/insertion mutations were only detected in the Lamivudine resistance group, while synonymous mutations were found in both groups. Follow-up analyses revealed that five patients in the Lamivudine group developed hepatocellular carcinoma, while patients in the Entecavir group did not. These mutants were characterized by a significant decrease in transactivation of the pre-S1 promoter, and varying effects on transactivation of the X promoter. Co-transfection of HBx-mutant plasmid and HBV replication-competent clone into HepG2 cells resulted in increased nuclear-to-cytoplamic HBV core antigen, HBV-DNA ratios, and nuclear covalently closed circular DNA (cccDNA). Antiviral drug sensitivity assays revealed that these mutants exhibited a compensatory effect to counteract antiviral drug suppression, resulting in elevated secretory HBV-DNA levels.

CONCLUSIONS

Our study demonstrates that HBx mutants can emerge during Lamivudine or Entecavir therapy. These mutants exhibit altered transactivation of the HBV pre-S1 and X promoters, leading to increased cccDNA levels to compensate for replication suppression.

T cell metabolism in chronic viral infection

T cells are a fundamental component of the adaptive immune response in the context of both acute and chronic viral infection. Tight control over the metabolic processes within T cells provides an additional level of immune regulation that is interlinked with nutrient sensing and the continued balancing of co-stimulatory and co-inhibitory signals. Underpinning T cell responsiveness for viral control are a number of phenotypic and functional adaptations ensuring adequate nutrient uptake and their utilization. T cells responding to persistent viral infections often exhibit a profile associated with immune cell exhaustion and a dysregulated metabolic profile, driven by a combination of chronic antigenic stimulation and signals from the local microenvironment. Understanding alterations in these metabolic processes provides an important basis for immunotherapeutic strategies to treat persistent infections.

Analysis of HBV X gene quasispecies characteristics by next-generation sequencing and cloning-based sequencing and its association with hepatocellular carcinoma progression

OBJECTIVES

This study aimed to describe the differences between next-generation sequencing (NGS) and cloning-based sequencing (CBS) in HBX quasispecies research and primitively investigate the relationship between the dominant HBX quasispecies and hepatocellular carcinoma (HCC).

METHODS

A total of 12 serum samples were collected. Serum hepatitis B virus (HBV) DNA was extracted, and the HBV X-region (HBX) was amplified by nested polymerase chain reaction (PCR). The PCR products were simultaneously tested with NGS and CBS to detect quasispecies of the HBX.

RESULTS

A total of 9348 eligible quasispecies sequences were obtained by NGS, which were much larger than the 98 of that by CBS. By the phylogenetic tree, the dominant quasispecies sequence of each sample could be found, although they had several nucleotides differences between the dominant quasispecies sequences found by CBS and NGS. By comparing the quasispecies heterogeneity, it was found that the quasispecies complexity value of HBV X-region obtained by NGS was higher than CBS (P < 0.05). The diversity values, including d, dS, dN, an d d N/ dS obtained by NGS were lower than by CBS (all of P < 0.01). The relativity of Spearman(rs) in d, dS, and dN were statistically significant (rs_ d = 0.865, P = 0.001; rs_ dS = 0.722, P = 0.014; and rs_ dN = 0.738, P = 0.011, respectively). There were 21 different bases between the HBX quasispecies of case A and control B.

CONCLUSION

The results of this can be used as guidance when researchers plan to choose a suitable method to study quasispecies, especially the HBV X gene quasispecies. Some high-risk mutations of HBX quasispecies were also found in this study and their relationship with HCC need deeper exploration.

Hepatitis B virus (HBV) X gene mutations and their association with liver disease progression in HBV-infected patients

Hepatitis B virus (HBV) is one of the most widespread human pathogens causing chronic hepatitis, liver cirrhosis, and hepatocellular carcinoma (HCC). This study investigated the clinical impact of single and combinational mutations in HBx gene on the pathogenesis of HCC during progressive stages of liver disease. The patients were categorized into inactive HBV carriers, active carriers, cirrhosis and HCC groups based on disease severity. Male sex, age > 50 years, and high serum alanine aminotransferase level were associated with risk of progressive liver disease. I127T, V131I, and F132Y/I/R mutations showed a significant increasing trend associated with the disease progression to HCC. H94Y and K130M mutations were also significantly associated with severe liver disease. One double mutation (K130M+V131I) and two triple mutations (I127T+K130M+V131L and K130M+V131I+F132Y) were observed, with significant rising prevalence through progressive clinical phases of liver disease to HCC. Several single and combinational mutations in HBx correlating with severity and progressive clinical phases of HBV infection were identified. The mutational combinations may have a synergistic effect in accelerating the progression to HCC. These specific patterns of HBx mutations can be useful in predicting the clinical outcome of HBV-infected patients and may serve as early markers of high risk of developing HCC.

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.

HBV X gene point mutations are associated with the risk of hepatocellular carcinoma: A systematic review and meta-analysis

Previous evidence suggests that the accumulation of the hepatitis B virus (HBV) X gene region point mutations may be associated with the development of hepatocellular carcinoma (HCC). However, the pathogenesis of HCC remains to be elucidated. The aim of the present meta-analysis was to investigate the association between the HBV X gene point mutations and the risk of HCC. Studies were collected regarding the association between HBV X gene point mutations and the risk of HCC, which were identified in PubMed, EMBASE and China National Knowledge Infrastructure databases. The results were evaluated by use of odds ratios (ORs) and its 95% confidence intervals (CIs), which were pooled by random or fixed effects. A total of 11 studies involving 2,502 patients were included in this meta-analysis. Statistical summary ORs of HBV X gene point mutations were obtained for T1653 (OR, 3.11; 95% CI, 2.22-4.36), V1753 (OR, 2.55; 95% CI, 1.66-3.92), and T1762/A1764 (OR, 4.49; 95% CI, 2.86-7.07). HBV X gene point mutations T1653, V1753 and T1762/A1764 could increase the risk of HCC significantly, particularly the T1762/A1764 double mutations. These mutations may be predictive for hepatocarcinogenesis. However, these results of the meta-analysis should be treated carefully due to a low level of evidence.

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.

Association between HBV Pre-S mutations and the intracellular HBV DNAs in HBsAg-positive hepatocellular carcinoma in China

This study aimed to investigate the association between HBV mutations and intrahepatic HBV status and to determine the clinical features and the contribution of HBV mutations to postoperative prognosis for hepatocellular carcinoma (HCC) patients with HBsAg (+) in China. Using TaqMan fluorescent real-time PCR, HBV covalently closed circular DNA (cccDNA) and total DNA (tDNA) were both quantified in 106 pairs of tumor tissues (TT) and adjacent non-tumor tissues (ANTT) obtained from HCC patients who received no antiviral treatment before surgical treatment. The prevalence of 19 hot spot mutations was evaluated by Sanger sequencing. HBV cccDNA and tDNA were lower in TT than in ANTT. The loads of cccDNA and tDNA in ANTT were associated with serum HBV DNA and HBeAg. Three Pre-S mutants (A2962G and C2964A in Pre-S1 and C105T in Pre-S2) were associated with higher tumor cccDNA levels (P < 0.05), and A2962G/C2964A mutants were associated with higher AFP levels. This would assist to disclose the virological features, to implement a more clinically personalized therapy and to improve the prognosis of HBV-related HCC patients.

Hepatitis B virus genetic mutations and evolution in liver diseases

Hepatitis B virus (HBV) belongs to the genus Orthohepadnavirus of the Hepadnaviridae family and is approximately 3.2 kb in length. Owing to a lack of proofreading capacity during reverse transcription and a high replication rate, HBV exhibits as quasispecies. To detect the genetic mutations of HBV, many methods with different sensitivities and throughputs were developed. According to documentary records, HBV mutation and evolution were important vial parameters in predicting disease progression and therapeutic outcome. In this review, we separately discussed the correlation between HBV genomic mutations in four open reading frames and liver disease progression. Since some of the results were controversial from different laboratories, it remains to be seen whether functional analyses will confirm their role in modifying the course of infection.

Clinicopathological characteristics of PIK3CA and HBx mutations in Korean patients with hepatocellular carcinomas

Hepatocellular carcinoma (HCC) is the fourth most common form of cancer in the Korean population, caused primarily by infection with either the Hepatitis B or C virus. Progression of this disease is frequently associated with mutations in either phosphoinositide-3-kinase, catalytic, alpha (PIK3CA) or hepatitis B virus X (HBx) gene. Previous studies have examined the frequency of PIK3CA mutations in HCC, although the clinical significance of these mutations has not been studied in a Korean population. In addition, HBx appears to play a key role in modulating a wide range of cellular functions, leading to HCC. In this study, we examined microdissected tumor samples from 50 HCC patients who underwent hepatectomy at Keimyung University Dongsan Medical Center. These patients were screened for mutations in PIK3CA and HBx to identify the clinical outcomes associated with these mutations. Exons 9 and 20 of PIK3CA and the entirety of HBx were screened for mutations by polymerase chain reaction and direct DNA sequencing. PIK3CA mutations were detected in 7 of 50 patients (14%). Among the 42 patients who were seropositive for hepatitis B, 17 (40.5%) had HBx mutations and 4 (9.52%) had mutations in PIK3CA. PIK3CA mutations were strongly correlated with tumor size. Patients harboring HBx mutations exhibited a longer time to recurrence; this difference was statistically significant not only in comparison with the PIK3CA mutation but also compared with those without any mutations. This result suggests a role for PIK3CA and HBx mutations as prognostic markers in HCC.

Mutation profiling of the hepatitis B virus strains circulating in North Indian population

AIMS

The aim of this study was to investigate the genomic mutations in the circulating Hepatitis B virus strains causing infection in the Indian population. Further, we wanted to analyze the biological significance of these mutations in HBV mediated disease.

METHODS

222 HBsAg positive patients were enrolled in the study. The genotype and mutation profile was determined for the infecting HBV isolate by sequencing overlapping fragments. These sequences were analyzed by using different tools and compared with previously available HBV sequence information. Mutation Frequency Index (MFI) for the Genes and Diagnosis group was also calculated.

RESULTS

HBV Genotype D was found in 55% (n = 121) of the patient group and genotype A was found in 30% (n = 66) of samples. The majority (52%) of the HBV-infected individuals in the present study were HBeAg-negative in all the age groups studied. Spontaneous drug associated mutations implicated in resistance to antiviral therapy were also identified in about quarter of our patients, which is of therapeutic concern. The MFI approach used in the study indicated that Core peptide was the most conserved region in both genotypes and Surface peptide had highest mutation frequency. Few mutations in X gene (T36A and G50R) showed high frequency of association with HCC. A rare recombinant strain of HBV genotype A and D was also identified in the patient group.

CONCLUSIONS

HBV genotype D was found out to be most prevalent. More than half of the patients studied had HBeAg negative disease. Core region was found to be most conserved. Drug Associated mutations were detected in 22% of the patient group and T36A and G50R mutations in X gene were found to be associated with HCC.

Molecular characterization of hepatitis B virus X gene in chronic hepatitis B patients

Background

HBV-X protein is associated with the pathogenesis of HBV related diseases, specially in hepatocellular carcinomas of chronic patients. Genetic variability of the X gene includes genotypic specific variations and mutations emerging during chronic infection. Its coding sequence overlaps important regions for virus replication, including the basal core promoter. Differences in the X gene may have implications in biological functions of the protein and thus, affect the evolution of the disease. There are controversial results about the consequences of mutations in this region and their relationship with pathogenesis. The purpose of this work was to describe the diversity of HBV-X gene in chronic hepatitis patients infected with different genotypes, according to liver disease.

Methods

HBV-X gene was sequenced from chronic hepatitis B patient samples, analyzed by phylogeny and genotyped. Nucleotide and aminoacid diversity was determined calculating intragenetic distances. Mutations at 127, 130 and 131 aminoacids were considered in relation to liver disease.

Results

The most prevalent genotype detected in this cohort was F (F1 and F4), followed by D and A. Most of the samples corresponding to genotypes A and F1 were HBeAg(+) and for genotypes D and F4, HBeAg(−) samples were represented in a higher percentage. Intragenetic distance values were higher in HBeAg(−) than in positive samples for all genotypes, and lower in overlapped regions, compared to single codification ones. Nucleotide and aminoacid diversities were higher in HBeAg(−), than in HBeAg(+) samples.

Conclusions

Independently of the infecting genotypes, mutations at any of 127, 130 and/or 131 aminoacid positions and HBeAg(−) status were associated with mild liver disease in this cohort.

Mutational complex genotype of the hepatitis B virus X /precore regions as a novel predictive marker for hepatocellular carcinoma

This study explored the combined effect of number and pattern of mutations in the X/precore regions of the hepatitis B virus (HBV) genome, mutational complex genotype (MCG), on hepatocellular carcinoma (HCC) development. Sequence variations were determined by direct sequencing and multiplex restriction fragment mass polymorphism analysis in 150 age-, sex- and hepatitis B e antigen (HBeAg) status-matched patients with and without HCC. In addition, a longitudinal study and an external validation of MCG were conducted. All were HBV subgenotype C2. Eight high-frequency mutations (G1613A, C1653T, T1753V, A1762T, G1764A, A1846T, G1896A and G1899A) were significantly associated with HCC. Whereas C1653T, T1753V, G1764A and A1846T were independent mutational factors for HCC, the significance of these individual mutations was negligible when analyzed with all clinico-virological variables. The total number of mutations was the only independent viral factor for HCC, irrespective of HBeAg status. There was a significant dose-risk relationship between the number of mutations and HCC, in which high risks for HCC were associated with mutation numbers ≥ 6. Pattern analysis of the mutations revealed disparity in distribution among the top seven high-risk mutation combination patterns, which accounted for 40 and 2.7% of HCC and non-HCC cases, respectively. The predictive accuracy of the high-risk mutations for HCC was similar to that of α-fetoprotein. Longitudinal and external validation studies also supported the association of mutation number with HCC development. MCG in the HBV X/precore regions is a risk indicator for HCC, and might serve as a new guide to the HCC screening scheme for chronic HBV carriers.

Impact of hepatitis B virus (HBV) x gene mutations on hepatocellular carcinoma development in chronic HBV infection

The hepatitis B virus (HBV) PreS mutations C1653T, T1753V, and A1762T/G1764A were reported as a strong risk factor of hepatocellular carcinoma (HCC) in a meta-analysis. HBV core promoter overlaps partially with HBx coding sequence, so the nucleotide 1762 and 1764 mutations induce HBV X protein (HBx) 130 and 131 substitutions. We sought to elucidate the impact of HBx mutations on HCC development. Chronically HBV-infected patients were enrolled in this study: 42 chronic hepatitis B (CHB) patients, 23 liver cirrhosis (LC) patients, and 31 HCC patients. Direct sequencing showed HBx131, HBx130, HBx5, HBx94, and HBx38 amino acid mutations were common in HCC patients. Of various mutations, HBx130+HBx131 (double) mutations and HBx5+HBx130+HBx131 (triple) mutations were significantly high in HCC patients. Double and triple mutations increased the risk for HCC by 3.75-fold (95% confidence interval [CI] = 1.101 to 12.768, P = 0.033) and 5.34-fold (95% CI = 1.65 to 17.309, P = 0.005), respectively, when HCC patients were compared to CHB patients. Functionally, there were significantly higher levels of NF-κB activity in cells with the HBx5 mutant and with the double mutants than that of wild-type cells and the triple-mutant cells. The triple mutation did not increase NF-κB activity. Other regulatory pathways seem to exist for NF-κB activation. In conclusion, a specific HBx mutation may contribute to HCC development by activating NF-κB activity. The HBx5 mutation in genotype C2 HBV appears to be a risk factor for the development of HCC and may be used to predict the clinical outcomes of patients with chronic HBV infection.

Association between Hepatitis B Virus X Gene Mutations and Clinical Status in Patients with Chronic Hepatitis B Infection

BACKGROUND/AIMS

Few reports have described the association between mutations in the entire X gene of the hepatitis B virus (HBV) and the clinical status of HBV-infected patients. We studied the association between HBV X gene mutations and the disease status of patients infected with HBV genotype C.

METHODS

Mutations in the HBV X genes of 194 patients were determined by direct sequencing. The subject population consisted of patients with chronic hepatitis (n=60), liver cirrhosis (n=65), and hepatocellular carcinoma (HCC) (n=69). The sequencing results of these 3 groups were compared.

RESULTS

Each of the mutations G1386M, C1485T, C1653T, T1753V, A1762T, and G1764A was significantly associated with the patient's clinical status. The T1753V (p<0.001) and A1762T/G1764A (p<0.001) mutations were found more frequently in Hepatitis B e antigen (HBeAg)-negative than in HBeAg-positive patients. Specific X gene mutations (G1386M, C1653T, and A1762T/G1764A) were more prevalent in patients with liver cirrhosis and HCC than in chronic hepatitis patients (p<0.005 for all). In addition, the T1753V (p<0.001) and C1485T (p<0.001) mutations were significantly more prevalent in HCC patients than in chronic hepatitis patients. Only the prevalence of the T1753V mutation increased as the HBV infection progressed from liver cirrhosis to HCC (p=0.023).

CONCLUSIONS

Our findings show a difference in the pattern of X gene mutations that were associated with the clinical status of patients with chronic HBV infection.

Characterization of the basal core promoter and precore regions in anti-HBe-positive inactive carriers of hepatitis B virus

BACKGROUND

The study of hepatitis B virus (HBV) genomic heterogeneity has become a major issue in investigations aimed at understanding the relationship between HBV mutants and the wide spectrum of clinical and pathological conditions associated with HBV infection. Although most chronically infected HBV patients are inactive carriers, several virological aspects of this state remain unclear.

METHODS

In order to determine the prevalence and clinical significance of mutations in the basal core promoter (BCP) and precore (pC) regions among inactive carriers, the nucleotide sequences from 41 inactive carriers were analyzed and compared with those from 29 individuals with chronic active hepatitis.

RESULTS

Genotypes A (24.3%), D (37.1%), F1b (12.9%), and F4 (18.6%) were the most prevalent. Mutations in the BCP/pC regions were observed in most of the inactive carriers (92.7%) and in most of the patients with chronic active hepatitis (93.1%). The prevalence of mutation 1764(A) was significantly higher in patients with chronic active hepatitis (65.5%) than in inactive carriers (36.6%) (p=0.038), whereas the prevalences of mutations at the other positions analyzed were not significantly different. Older patients (>50 years) showed BCP/pC patterns with a higher number of substitutions. Mutations were found to be biased by genotype: the 1896(A) mutation was highly prevalent in genotypes D and F4, while alternative substitutions in the pC region were more prevalent in genotypes A and F1b.

CONCLUSIONS

Mutations in the BCP/pC regions are the hallmark of chronic anti-HBe-positive individuals; nevertheless, the even distribution of mutations in active and inactive carriers suggests that BCP/pC mutations may occur during HBV infection not strictly related to the HBV infection activity.

A matched case-control study of hepatitis B virus mutations in the preS and core promoter regions associated independently with hepatocellular carcinoma

This study aimed to determine hepatitis B virus (HBV) mutations associated independently with the risk of hepatocellular carcinoma (HCC), as adjusted with other mutations in the preS and core promoter regions of HBV genotypes B and C. One hundred and forty HBV-infected patients with HCC and 280 HBV-infected patients without HCC who had intact data of HBV genotyping and DNA sequencing in both regions were involved in this age-, sex-matched case-control study. Univariate and two-step stepwise multivariate regression analyses were performed to determine factors associated with the risk of HCC. Of 39 mutations evaluated, 23 in genotype C and 6 in genotype B were associated with an increased risk of HCC in the univariate analysis. Multivariate analyses established that genotype C (adjusted odds ratio [AOR] = 3.3; 95% confidence interval [CI] = 1.1-9.8), viral load (≥10(4) copies/ml) (AOR = 2.4; 95% CI = 1.0-5.8), A2962G (AOR = 18.7; 95% CI = 7.5-46.7), preS2 start codon mutation (AOR = 12.5; 95% CI = 3.4-45.5), C105T (AOR = 0.1; 95% CI = 0.0-0.2), T1753V (AOR = 3.1; 95% CI = 1.1-9.2), and A1762T/G1764A (AOR = 2.9; 95% CI = 1.1-7.3) were associated independently with HCC, adjusted for factors including mutations in both regions. By using an estimating haplotype frequencies program, it was found that a haplotypic carriage with 105C and 2962G was significantly more frequent in the patients with HCC than in those without HCC and the frequency of haplotype 2962G-preS2 start codon wildtype-105C-1762T/1764A was 47.9% in the patients with HCC and 4.3% in those without HCC. Conclusively, A2962G and T105C are novel factors associated independently with HCC. Further prospective studies are needed to confirm the role of these mutations in the development of HCC.

Association between the various mutations in viral core promoter region to different stages of hepatitis B, ranging of asymptomatic carrier state to hepatocellular carcinoma

OBJECTIVES

The objective of this study was to determine the association of 19 mutations with frequencies ≥ 10% in the core promoter region of hepatitis B virus (HBV) with chronic hepatitis B (CHB), liver cirrhosis, and hepatocellular carcinoma (HCC).

METHODS

Eight hundred forty-six asymptomatic hepatitis B surface antigen carriers (ASCs), 235 CHB patients, 188 cirrhosis patients, and 190 HCC patients with intact data of HBV genotyping, DNA sequencing, and serological parameters were studied. Nucleotides with the highest frequencies in HBV genotypes B and C from all ASCs were treated as wild-type nucleotides.

RESULTS

Mutations at nt.1674, nt.1719, nt.1762, nt.1764, nt.1846, nt.1896, and nt.1913 in genotype C were significantly associated with CHB, cirrhosis, and HCC, as compared with ASCs. C1673T, A1726C, A1727T, C1730G, C1766T, T1768A, C1773T, and C1799G in genotype C were significantly associated with cirrhosis compared with the CHB patients, whereas these mutations were inversely associated with HCC compared with the cirrhosis patients. Multivariate regression analyses showed that age, male, abnormal alanine aminotransferase (ALT), T1768A, A1762T/G1764A, and A1846T were independently associated with cirrhosis compared with ASCs and the patients with CHB. Age, abnormal ALT, HBV DNA (≥10(4) copies/ml), genotype C, C1653T, T1674C/G, T1753V, and A1762T/G1764A were independently associated with HCC compared with those without HCC. Haplotypic carriages with two or more HBV mutations were significantly associated with HCC. T1674C/G, C1653T, and T1753V were specific for HCC. A1762T/G1764A had a moderate sensitivity and specificity for HCC.

CONCLUSIONS

C1673T, A1726C, A1727T, C1730G, C1766T, T1768A, C1773T, and C1799G in genotype C are specific for cirrhosis. A1846T and T1674C/G are novel factors independently associated with cirrhosis and HCC, respectively.

Clinical relevance and public health significance of hepatitis B virus genomic variations

Ten hepatitis B virus (HBV) genotypes (A-J) and 34 HBV subgenotypes have been identified so far. HBV genotypes and subgenotypes have distinct geographical distributions, and have been shown to differ with regard to clinical outcome, prognosis, and response to interferon treatment. Infection with subgenotype A2 is frequently associated with high viral load, resulting in acute infection via horizontal transmission. Genotypes A and B are more sensitive to interferon treatment than genotypes D and C, respectively. Genotype B is more frequent in acute hepatitis than genotype C, whereas genotype C (C2) is more frequently associated with an increased risk of hepatocellular carcinoma (HCC), mostly cirrhotic, as compared with genotype B (B2). Genotype mixture is associated with high viral load and worse outcome of HBV infection. HBV mutations in the S genes, especially amino acids substitution at position 145 (G145R), are associated with immune escape, whereas mutations in the PreS or S genes which impair HBsAg secretion could present a risk to blood safety. HBV variants harboring mutations in the viral polymerase gene that confer resistance to nucleoside analogs may be selected during antiviral therapy. Different genotypes have distinct mutation patterns in the PreS and EnhII/BCP/Precore regions. PreS deletions, C1653T, T1753V, and A1762T/G1764A are associated with an increased risk of HCC. HCC-associated HBV mutants may not transmit via mother-to-child transmission, and are likely generated during HBV-induced pathogenesis. Examination of HBV mutations alone or in combination and host genetic susceptibility will be helpful in classifying the HBV-infected subjects who will develop HCC and need active anti-viral treatments.

Clinical relevance and public health significance of hepatitis B virus genomic variations

Ten hepatitis B virus (HBV) genotypes (A-J) and 34 HBV subgenotypes have been identified so far. HBV genotypes and subgenotypes have distinct geographical distributions, and have been shown to differ with regard to clinical outcome, prognosis, and response to interferon treatment. Infection with subgenotype A2 is frequently associated with high viral load, resulting in acute infection via horizontal transmission. Genotypes A and B are more sensitive to interferon treatment than genotypes D and C, respectively. Genotype B is more frequent in acute hepatitis than genotype C, whereas genotype C (C2) is more frequently associated with an increased risk of hepatocellular carcinoma (HCC), mostly cirrhotic, as compared with genotype B (B2). Genotype mixture is associated with high viral load and worse outcome of HBV infection. HBV mutations in the S genes, especially amino acids substitution at position 145 (G145R), are associated with immune escape, whereas mutations in the PreS or S genes which impair HBsAg secretion could present a risk to blood safety. HBV variants harboring mutations in the viral polymerase gene that confer resistance to nucleoside analogs may be selected during antiviral therapy. Different genotypes have distinct mutation patterns in the PreS and EnhII/BCP/Precore regions. PreS deletions, C1653T, T1753V, and A1762T/G1764A are associated with an increased risk of HCC. HCC-associated HBV mutants may not transmit via mother-to-child transmission, and are likely generated during HBV-induced pathogenesis. Examination of HBV mutations alone or in combination and host genetic susceptibility will be helpful in classifying the HBV-infected subjects who will develop HCC and need active anti-viral treatments.