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

Cancer Evo-Dev: A Theory of Inflammation-Induced Oncogenesis

Chronic inflammation is a prerequisite for the development of cancers. Here, we present the framework of a novel theory termed as Cancer Evolution-Development (Cancer Evo-Dev) based on the current understanding of inflammation-related carcinogenesis, especially hepatocarcinogenesis induced by chronic infection with hepatitis B virus. The interaction between genetic predispositions and environmental exposures, such as viral infection, maintains chronic non-resolving inflammation. Pollution, metabolic syndrome, physical inactivity, ageing, and adverse psychosocial exposure also increase the risk of cancer via inducing chronic low-grade smoldering inflammation. Under the microenvironment of non-resolving inflammation, pro-inflammatory factors facilitate the generation of somatic mutations and viral mutations by inducing the imbalance between the mutagenic forces such as cytidine deaminases and mutation-correcting forces including uracil-DNA glycosylase. Most cells with somatic mutations and mutated viruses are eliminated in survival competition. Only a small percentage of mutated cells survive, adapt to the hostile environment, retro-differentiate, and function as cancer-initiating cells via altering signaling pathways. These cancer-initiating cells acquire stem-ness, reprogram metabolic patterns, and affect the microenvironment. The carcinogenic process follows the law of "mutation-selection-adaptation". Chronic physical activity reduces the levels of inflammation via upregulating the activity and numbers of NK cells and lymphocytes and lengthening leukocyte telomere; downregulating proinflammatory cytokines including interleukin-6 and senescent lymphocytes especially in aged population. Anti-inflammation medication reduces the occurrence and recurrence of cancers. Targeting cancer stemness signaling pathways might lead to cancer eradication. Cancer Evo-Dev not only helps understand the mechanisms by which inflammation promotes the development of cancers, but also lays the foundation for effective prophylaxis and targeted therapy of various cancers.

Hepatitis B and Pregnancy: Virologic and Immunologic Characteristics

The hepatitis B virus (HBV) is an important human pathogen. Unvaccinated infants infected through mother-to-child transmission (MTCT) are at >95% risk of developing serum hepatitis B surface antigen-positive chronic hepatitis B (CHB). Despite complete passive-active HBV immunoprophylaxis, approximately 10% of infants born to mothers who are highly viremic develop CHB, and thus maternal treatment with nucleos(t)ide analogs (tenofovir disoproxil fumarate, lamivudine, or telbivudine) is recommended in the third trimester of pregnancy to reduce MTCT risk. Viral rebound usually occurs after stopping treatment and, in the context of maternal immunologic reconstitution postpartum, can also precipitate host immune-mediated hepatic (biochemical) flares. In this article, we review the epidemiology of HBV MTCT, discuss management and potential mechanisms of HBV vertical transmission, and highlight recent studies on virologic and immunologic aspects of hepatitis B in pregnancy and postpartum.

Natural History of Chronic Hepatitis B Virus Infection in Ahvaz City, Iran

Objective: A long persistent of Chronic Hepatitis B (CHB) infection may develop liver cirrhosis or hepatocellular carcinoma (HCC) and about one million people die due to HBV -related liver cancer and end-stage liver disease annually worldwide. The natural history of CHB phases comprises four phases: immune tolerant (HBeAg detectable and ALT (Alanine Transaminase) normal, HBeAg-positive immune active (HBeAg detectable, anti-HBe antibodies undetectable and ALT persistently elevated), HBeAg-negative immune active (HBeAg undetectable, anti-HBe antibodies present and ALT persistently elevated), inactive carrier (HBeAg undetectable, anti-HBe antibodies present and ALT normal). The evaluation of chronic hepatitis B phases is a crucial to manage the burden of disease and limit the development of associated complications, such as cirrhosis and hepatocellular carcinoma (HCC). Thus this study conducted to evaluate the natural history of HBV infection in patients with chronic HBV infection in Ahvaz city, Iran. Methods: In this study, 71 non-treated CHB individuals were recruited including 44 (62%) males and 27(38%) females. The sera were tested for HBV markers, HBsAg, HBcIgG, HBeAg, and HBeAb. ALT assay and HBV viral load were carried out for each CHB individual. Results: Based on the analysis of serological, ALT status and viral load, the results showed: immune tolerance 5(7%), eAg+ Immune Clearance 14(19.7%), eAg- Immune Clearance 29 (40.84%) and Inactive Carrier 23 (32.39%). The HBeAg seroconversion was observed in a male age 18 year. Conclusion: The results of the natural history of individuals with chronic hepatitis B phases CHB shows immune tolerance (7%), eAg+ Immune Clearance (19.7%), eAg- Immune Clearance (40.84%) and Inactive Carrier (32.39%). To prevent the consequence of CHB infection, an individual in immune tolerance phase should be tested periodically for ALT level, HBV markers, HBsAg, HBcIgG, HBeAg, HBeAb and HBV viral load. Then decision-making therapy can be applied for CHB patients at early stage of immune clearance.

Deep sequencing of HBV pre-S region reveals high heterogeneity of HBV genotypes and associations of word pattern frequencies with HCC

Hepatitis B virus (HBV) infection is a common problem in the world, especially in China. More than 60–80% of hepatocellular carcinoma (HCC) cases can be attributed to HBV infection in high HBV prevalent regions. Although traditional Sanger sequencing has been extensively used to investigate HBV sequences, NGS is becoming more commonly used. Further, it is unknown whether word pattern frequencies of HBV reads by Next Generation Sequencing (NGS) can be used to investigate HBV genotypes and predict HCC status. In this study, we used NGS to sequence the pre-S region of the HBV sequence of 94 HCC patients and 45 chronic HBV (CHB) infected individuals. Word pattern frequencies among the sequence data of all individuals were calculated and compared using the Manhattan distance. The individuals were grouped using principal coordinate analysis (PCoA) and hierarchical clustering. Word pattern frequencies were also used to build prediction models for HCC status using both K-nearest neighbors (KNN) and support vector machine (SVM). We showed the extremely high power of analyzing HBV sequences using word patterns. Our key findings include that the first principal coordinate of the PCoA analysis was highly associated with the fraction of genotype B (or C) sequences and the second principal coordinate was significantly associated with the probability of having HCC. Hierarchical clustering first groups the individuals according to their major genotypes followed by their HCC status. Using cross-validation, high area under the receiver operational characteristic curve (AUC) of around 0.88 for KNN and 0.92 for SVM were obtained. In the independent data set of 46 HCC patients and 31 CHB individuals, a good AUC score of 0.77 was obtained using SVM. It was further shown that 3000 reads for each individual can yield stable prediction results for SVM. Thus, another key finding is that word patterns can be used to predict HCC status with high accuracy. Therefore, our study shows clearly that word pattern frequencies of HBV sequences contain much information about the composition of different HBV genotypes and the HCC status of an individual.

HBV infection can lead to many liver complications including hepatocellular carcinoma (HCC), one of the most common liver cancers in China. High-throughput sequencing technologies have recently been used to study the genotype sequence compositions of HBV infected individuals and to distinguish chronic HBV (CHB) infection from HCC. We used NGS to sequence the pre-S region of a large number of CHB and HCC individuals and designed novel word pattern based approaches to analyze the data. We have several surprising key findings. First, most HBV infected individuals contained mixtures of genotypes B and C sequences. Second, multi-dimensional scaling (MDS) analysis of the data showed that the first principal coordinate was closely associated with the fraction of genotype B (or C) sequences and the second principal coordinate was highly associated with the probability of HCC. Third, we also designed K-nearest neighbors (KNN) and support vector machine (SVM) based classifiers for CHB and HCC with high prediction accuracy. The results were validated in an independent data set.

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.

Natural history of acute and chronic hepatitis B: The role of HBV genotypes and mutants

Molecular epidemiologic studies reveal remarkable differences in the geographical distribution of hepatitis B virus (HBV) genotypes. The frequency of mutants among HBV genotypes also varies. The role of HBV genotypes/mutants in the pathogenesis of HBV infection and natural history of HBV infection has been extensively investigated. The distribution of HBV genotypes in acute hepatitis B patients reflects the predominant genotypes in a given geographic area. In chronic hepatitis B patients, genotype C and D have a higher frequency of basal core promoter A1762T/G1764A mutations than genotype A and B. HBV genotypes C, D and F carry a higher lifetime risk of cirrhosis and HCC development than genotype A and B. HBV pre-S/S gene mutations were associated with immune escape of hepatitis B immunoglobulin or vaccine-induced immunity. Mutations in the pre-S, core promoter and X regions correlate with an increased risk of cirrhosis and HCC. In summary, HBV genotypes and mutants are associated with the disease progression and long-term outcome of HBV infection. They may serve as viral genetic markers for risk stratification of chronic hepatitis B patients in clinical practice.

Higher prevalence of cancer related mutations 1762T/1764A and PreS deletions in hepatitis B virus (HBV) isolated from HBV/HIV co-infected compared to HBV-mono-infected Chinese adults

In the era of combination therapy for human immunodeficiency virus (HIV), liver disease including hepatocellular carcinoma (HCC), are the major causes of death for patients co-infected with hepatitis B virus (HBV) and HIV. However, the mechanisms remain obscure. We aimed to determine whether HCC-related HBV mutations including 1762T/1764A double mutation and pre-S deletions occur more frequently in HBV/HIV co-infected individuals compared to HBV mono-infected individuals. In this study, the basic core promoter (BCP) and the preS/S regions of HBV isolated from 61 pairs of HBV/HIV co-infected and HBV mono-infected participants were analyzed. We found that the prevalence of HBV isolates with 1762T/1764A and/or preS deletion mutations was 37.7% (95% CI: 29.1-46.3). The prevalence of these mutations in HBV/HIV co-infected group (52.5%, 95% CI: 40.0-65.0) was significantly higher than in the HBV mono-infected group (23.0%, 95% CI: 12.4-33.6) (X²=11.307, P<0.05). HBV/HIV co-infection was associated with higher viral loads but these higher viral loads were not associated with the higher prevalence of HCC-related HBV mutations. Individually 1762T1764A (44.3%) or preS deletions (23%) occurred more frequently in isolates from co-infected compared to mono-infected individuals (21.3%, 4.9%, respectively) (X²=7.290, P<0.05; X²=8.270, P<0.05). Moreover, 1762T/1764A and preS deletions occurred more frequently in genotypes C and I compared to genotype B (p<0.05). Multivariate analysis revealed that co-infection with HIV was associated with the development of both 1762T/1764A ((RR: 2.932(1.325-6.488)) and preS deletions ((RR: 5.759(1.562-21.235)). These results demonstrate that co-infection with HIV was associated with increased prevalence of HCC-related mutations in HBV isolates from Chinese patients.

Prediction and prophylaxis of hepatocellular carcinoma occurrence and postoperative recurrence in chronic hepatitis B virus-infected subjects

Hepatocellular carcinoma (HCC) is one of the most common and highly fatal malignancies worldwide. Chronic infection with hepatitis B virus (HBV) is a major cause of HCC. High HBV replication rate and related non-resolving inflammation are the major risk factors of HCC occurrence and postoperative recurrence. Early prophylactic options are effective in reducing HCC occurrence and improving survival. Therefore, it is important to identify HBV-infected patients who are at a higher risk of developing HCC and HBV-HCC patients who are more likely to relapse after surgery, thus providing them with more precise prophylactic strategies. Several prediction models of HCC occurrence have been constructed, with satisfactory predictive accuracy and discriminatory ability. However, there is a lack of consensus for their clinical implementation. Several staging systems have been proposed for HCC prognosis. However, the accuracy of these staging systems based on demographic characteristics and clinical measurements needs to be further improved, possibly by systematically incorporating viral and inflammatory factors. Since antiviral treatments are effective in promoting liver function reserve, reducing HCC occurrence and prolonging postoperative survival in some HBV-infected subjects, it is very important to identify subgroups of HBV-infected patients who would most benefit from antiviral treatment.

Overview of hepatitis B viral replication and genetic variability

Chronic infection with hepatitis B virus (HBV) greatly increases the risk for liver cirrhosis and hepatocellular carcinoma (HCC). HBV isolates worldwide can be divided into ten genotypes. Moreover, the immune clearance phase selects for mutations in different parts of the viral genome. The outcome of HBV infection is shaped by the complex interplay of the mode of transmission, host genetic factors, viral genotype and adaptive mutations, as well as environmental factors. Core promoter mutations and mutations abolishing hepatitis B e antigen (HBeAg) expression have been implicated in acute liver failure, while genotypes B, C, subgenotype A1, core promoter mutations, preS deletions, C-terminal truncation of envelope proteins, and spliced pregenomic RNA are associated with HCC development. Our efforts to treat and prevent HBV infection are hampered by the emergence of drug resistant mutants and vaccine escape mutants. This paper provides an overview of the HBV life cycle, followed by review of HBV genotypes and mutants in terms of their biological properties and clinical significance.

Sequence analysis of sub-genotype D hepatitis B surface antigens isolated from Jeddah, Saudi Arabia

Little is known about the prevalence of HBV genotypes/sub-genotypes in Jeddah province, although the hepatitis B virus (HBV) was identified as the most predominant type of hepatitis in Saudi Arabia. To characterize HBV genotypes/sub-genotypes, serum samples from 15 patients with chronic HBV were collected and subjected to HBsAg gene amplification and sequence analysis. Phylogenetic analysis of the HBsAg gene sequences revealed that 11 (48%) isolates belonged to HBV/D while 4 (18%) were associated with HBV/C. Notably, a HBV/D sub-genotype phylogenetic tree identified that eight current isolates (72%) belonged to HBV/D1, whereas three isolates (28%) appeared to be more closely related to HBV/D5, although they formed a novel cluster supported by a branch with 99% bootstrap value. Isolates belonging to D1 were grouped in one branch and seemed to be more closely related to various strains isolated from different countries. For further determination of whether the three current isolates belonged to HBV/D5 or represented a novel sub-genotype, HBV/DA, whole HBV genome sequences would be required. In the present study, we verified that HBV/D1 is the most prevalent HBV sub-genotype in Jeddah, and identified novel variant mutations suggesting that an additional sub-genotype designated HBV/DA should be proposed. Overall, the results of the present HBsAg sequence analyses provide us with insights regarding the nucleotide differences between the present HBsAg/D isolates identified in the populace of Jeddah, Saudi Arabia and those previously isolated worldwide. Additional studies with large numbers of subjects in other areas might lead to the discovery of the specific HBV strain genotypes or even additional new sub-genotypes that are circulating in Saudi Arabia.

Cancer Evolution-Development: experience of hepatitis B virus-induced hepatocarcinogenesis

Here, we present the basic concept and theoretical framework of a scientific hypothesis called Cancer Evolution-Development ("Cancer Evo-Dev"), based on our recent studies of the molecular mechanisms by which chronic infection with the hepatitis B virus induces hepatocarcinogenesis, together with related advances in that field. Several aspects central to our hypothesis are presented: ■ Immune imbalance-caused by the interaction of genetic predispositions and environmental exposures such as viral infection-is responsible for the maintenance of chronic non-resolving inflammation. Non-resolving inflammation promotes the occurrence and progression of cancers, characterized by an evolutionary process of "mutation-selection-adaptation" for both viruses and host cells.■ Under a microenvironment of non-resolving inflammation, proinflammatory factors promote mutations in viral or host genomes by transactivation of the expression of cytidine deaminases and their analogues. Most cells with genomic mutations and mutated viruses are eliminated in the competition for survival in the inflammatory microenvironment. Only a small percentage of the mutated cells that alter their survival signal pathways and exhibit the characteristics of "stem-ness" can survive and function as cancer-initiating cells.■ Cancers generally develop with properties of "backward evolution" and "retro-differentiation," indicating the indispensability of stem-like signal pathways in the evolution and development of cancers. The hypothesis of Cancer Evo-Dev not only lays the theoretical foundation for understanding the mechanisms by which inflammation promotes the development of cancers, but also plays an important role in specific prophylaxis, prediction, early diagnosis, and targeted treatment of cancers.

Genetic variation of hepatitis B virus and its significance for pathogenesis

Hepatitis B virus (HBV) has a worldwide distribution and is endemic in many populations. Due to its unique life cycle which requires an error-prone reverse transcriptase for replication, it constantly evolves, resulting in tremendous genetic variation in the form of genotypes, sub-genotypes, and mutations. In recent years, there has been considerable research on the relationship between HBV genetic variation and HBV-related pathogenesis, which has profound implications in the natural history of HBV infection, viral detection, immune prevention, drug treatment and prognosis. In this review, we attempted to provide a brief account of the influence of HBV genotype on the pathogenesis of HBV infection and summarize our current knowledge on the effects of HBV mutations in different regions on HBV-associated pathogenesis, with an emphasis on mutations in the preS/S proteins in immune evasion, occult HBV infection and hepatocellular carcinoma (HCC), mutations in polymerase in relation to drug resistance, mutations in HBV core and e antigen in immune evasion, chronicalization of infection and hepatitis B-related acute-on-chronic liver failure, and finally mutations in HBV x proteins in HCC.

Hepatitis B virus genotype, mutations, human leukocyte antigen polymorphisms and their interactions in hepatocellular carcinoma: a multi-centre case-control study

Three genome-wide association studies (GWAS) have been conducted on the genetic susceptibility of hepatitis B virus (HBV)-related hepatocellular carcinoma (HCC), two of which consistently identified tagging single nucleotide polymorphisms (SNPs) around HLA-DQ/DR. In contrast, large multi-centre association studies between HBV genotype, mutations and the risk of HCC are relatively rare, and their interactions with host variants are even less. We performed a multi-centre study of 1,507 HBV-related HCC cases and 1,560 HBV persistent carriers as controls to evaluate the effects of HBV genotype, mutations, GWAS-identified HLA-DQ/DR SNPs (rs9272105 and rs9275319) and their interactions on HCC risk. We found HBV genotype C was more frequent in HBV-related HCC. And 11 HBV hotspot mutations were independently and significantly associated with HCC risk. We also detected significant interactions of rs9272105 with both the HBV genotype and mutations. Through stepwise regression analysis, HBV genotype, the 11 mutations, HLA-DQ/DR SNPs, and the interaction of rs9272105 with mutation A1752G were all entered into the HCC prediction model, and the area under the curve for the panel including the HLA-DQ/DR SNPs, HBV genotype and mutations was 0.840. The HBV genotype, the mutations and the HLA-DQ/DR SNPs may serve as biomarkers for the surveillance of HBV persistent carriers.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

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.

Effect of functional nuclear factor-kappaB genetic polymorphisms on hepatitis B virus persistence and their interactions with viral mutations on the risk of hepatocellular carcinoma

BACKGROUND

Nonresolving inflammation and viral mutations are important in hepatitis B virus (HBV)-induced hepatocarcinogenesis. However, the effects of genetic polymorphisms affecting nuclear factor-kappaB (NF-κB) on HBV persistence and generation of hepatocellular carcinoma (HCC)-related HBV mutations remain unknown.

PATIENTS AND METHODS

rs28362491 (NFKB1 -94Ins > Del), rs2233406 (NFKBIA -826C > T), rs3138053 (NFKBIA -881A > G), and rs696 (NFKBIA +2758G > A) were genotyped in 1342 healthy controls, 327 HBV-clearance subjects, and 3976 HBV-positive subjects including 1495 HCC patients, using quantitative PCR. HBV mutations were determined by sequencing. The NFKBIA promoter activity was assessed by transient transfection. Multiplicative interactions of the polymorphisms and viral mutations were assessed by multivariate logistic regression.

RESULTS

Compared with HBV-clearance subjects, rs2233406 (CT versus CC) and rs3138053 (AG or AG + GG versus AA) significantly decreased HBV persistence, especially in the genotype B HBV-infected subjects. In the genotype C HBV-infected subjects, rs2233406 variant genotypes were significantly associated with an increased risk of HCC [CT versus CC: age-, gender-adjusted odds ratio (AOR), 1.33; 95% confidence interval (CI) 1.01-1.75 in training set and AOR, 1.59; 95% CI 1.01-2.52 in validation set] compared with HCC-free HBV-infected subjects and significantly increased the frequencies of HCC-related HBV mutations (A1762T/G1764A, T1753V, preS1 start codon mutation, and preS deletion); rs28362491 (Del/Del or Ins/Del + Del/Del versus Ins/Ins) significantly increased the frequency of A1762T/G1764A and reduced the frequency of preS2 start codon mutation. The variant genotypes impaired NFKBIA promoter activity in hepatic cells. The interaction of rs2233406 variant genotypes (CT + TT versus CC) with A1762T/G1764A significantly increased HCC risk in genotype C HBV-infected subjects, with AOR of 2.61 (95% CI 1.09-6.26).

CONCLUSION

Genetic polymorphisms improving NF-κB activity contribute to genotype B HBV clearance. The rs2233406 variant genotypes significantly increase HCC risk, possibly via facilitating immune selection of the HBV mutations. The host-virus interactions are important in identifying HBV-infected subjects who are more likely to develop HCC.

Occult hepatitis B virus infection and hepatocellular carcinoma: a systematic review

Occult hepatitis B (OHB) infection has been reported to play an important role in the development of hepatocellular carcinoma (HCC). In this systematic review, a significantly higher prevalence of OHB was observed in patients with HCC in the presence or absence of HCV infection when compared with control populations without HCC. Correspondingly, among adequately designed prospective studies, the cumulative probability of developing HCC was significantly greater among patients with OHB than among HBV DNA-negative patients in the presence or absence of HCV infection. Study design, inclusion criteria, treatment options, methodology and potential confounding variables were evaluated, and immunopathogenic mechanisms that could be involved in OHB as a risk factor in HCC were reviewed. From this analysis, we conclude that although OHB is an independent risk factor in HCC development in anti-HCV-negative patients, a synergistic or additive role in the occurrence of HCC in HCV-coinfected patients is more problematic due to the HCC risk attributable to HCV alone, especially in patients with advanced fibrosis and cirrhosis.

Human cytidine deaminases facilitate hepatitis B virus evolution and link inflammation and hepatocellular carcinoma

During hepatitis B virus (HBV)-induced hepatocarcinogenesis, chronic inflammation facilitates the evolution of hepatocellular carcinoma (HCC)-promoting HBV mutants. Cytidine deaminases, whose expression is stimulated by inflammatory cytokines and/or chemokines, play an important role in bridging inflammation and HCC. Through G-to-A hypermutation, cytidine deaminases inhibit HBV replication and facilitate the generation of HCC-promoting HBV mutants including C-terminal-truncated HBx. Cytidine deaminases also promote cancer-related somatic mutations including TP53 mutations. Their editing efficiency is counteracted by uracil-DNA glycosylase. Understanding the effects of cytidine deaminases in HBV-induced hepatocarcinogenesis and HCC progression will aid in developing efficient prophylactic and therapeutic strategies against HCC in HBV-infected population.

A complete genomic analysis of hepatitis B virus isolated from 516 Chinese patients with different clinical manifestations

This study investigated features and clinical implications of HBV mutations in patients with different clinical manifestations. In total, 516 patients were enrolled in this study, including 131 patients with acute hepatitis B, 239 patients with chronic hepatitis B, and 146 patients with acute-on-chronic liver failure. HBV genotypes and mutations were analyzed by direct sequencing of complete viral genomes. Genotypes B2, C1, C2, and D1 accounted for 22.2%, 1.6%, 74.6%, and 1.6%, respectively. Genotype B was more frequently detected in patients with acute hepatitis B than those with chronic hepatitis B and acute-on-chronic liver failure. Deletion mutations were detected mostly in preS1 and preS2 regions and the detection rates were 3.8%, 19.7%, and 24.7% for acute hepatitis B, chronic hepatitis B and acute-on-chronic liver failure patients, respectively. Incidences of point mutation T53C (preS1F53L), G1613A (polR841K), G1775A and A1762T + G1764A in the basal core promoter region, G1896A and G1899A in precore region and A2189C (coreI97L) in core region increased along with acute hepatitis B, chronic hepatitis B, and acute-on-chronic liver failure. The mutation G1896A was independently associated with poor survival of patients with acute-on-chronic liver failure. The gradual increase of viral mutation incidences was also observed in three HLA-A2-restricted cytotoxic T lymphocyte epitopes from HLA-A2-positive patients, that is env188-196 (5.8%, 10.1%, 22.5%), core107-115 (4.3%, 4.6%, 19.7%), and x92-100 (1.4%, 20.2%, 33.8%). In conclusion, certain viral mutations in various regions of HBV genome are associated with disease progression of HBV infection.

Combined core promoter mutations and pre-S deletion of HBV may not increase the risk of HCC: a geographical epidemiological study in Guangxi, China

BACKGROUND

Although persistent hepatitis B virus (HBV) infection is a major cause of hepatocellular carcinoma (HCC), the mechanisms of oncogenesis remain obscure.

AIMS

To determine whether the findings that HBV basal core promoter (BCP) A1762T, G1764A double mutations, pre-S deletions and a combination of both are risk factors of HCC are supported by geographical epidemiology.

METHODS

Study subjects were recruited from Long An county, where the incidence of HCC is the highest, and five other counties in Guangxi, where the HCC incidence is lower and varies among them. The Pre-S region and BCP of HBV from all study subjects were amplified and sequenced and the data were analysed using chi-squared tests.

RESULTS

The prevalence of BCP and pre-S mutations differs significantly (χ(2) = 9.850, 5.135, respectively, all P < 0.01) between Long An and the other counties. However, the prevalence of combined BCP and pre-S mutations does not differ significantly (χ(2) = 1.510, P > 0.05). These mutations are less frequent in the young but the prevalence of pre-S deletions does not increase with age. The prevalence of these mutations does not differ significantly between men and women but is significantly higher in Zhuang than the other ethnic populations. Among the other five counties, the prevalence of BCP mutations in counties where the HCC incidence is high is significantly higher than that of counties where the HCC incidence is low.

CONCLUSIONS

Combined BCP double mutations and pre-S deletion may not increase the risk of HCC, although these mutations are a risk factor of HCC when they present alone.

Hepatitis B virus genetic variants: biological properties and clinical implications

Hepatitis B virus (HBV) causes a chronic infection in 350 million people worldwide and greatly increases the risk of liver cirrhosis and hepatocellular carcinoma. The majority of chronic HBV carriers live in Asia. HBV can be divided into eight genotypes with unique geographic distributions. Mutations accumulate during chronic infection or in response to external pressure. Because HBV is an RNA-DNA virus the emergence of drug resistance and vaccine escape mutants has become an important clinical and public health concern. Here, we provide an overview of the molecular biology of the HBV life cycle and an evaluation of the changing role of hepatitis B e antigen (HBeAg) at different stages of infection. The impact of viral genotypes and mutations/deletions in the precore, core promoter, preS, and S gene on the establishment of chronic infection, development of fulminant hepatitis and liver cancer is discussed. Because HBV is prone to mutations, the biological properties of drug-resistant and vaccine escape mutants are also explored.

Synergistic effects of A1896, T1653 and T1762/A1764 mutations in genotype c2 hepatitis B virus on development of hepatocellular carcinoma

The effects of genomic changes in hepatitis B virus (HBV) on the occurrence of hepatocellular carcinoma (HCC) are still unclear, especially in relation to the genotype of HBV. In this study, we examined the effects of genomic changes in HBV of genotype C2 on the development of HCC. A total of 318 patients with HBV-associated HCC and 234 patients with chronic hepatitis B (CHB) were studied. All of HCC cases were diagnosed histologically and treated with surgical resection. The whole of the X, S, basal core promoter (BCP) and precore regions of the viral genome from sera or liver tissues were sequenced. All subjects had HBV of genotype C2. The prevalence of the T1653 mutation in the X region and the A1896 mutation in the precore region of HBV was significantly higher in the HCC group than in the control CHB group (22% vs 11%, P = 0.003; 50% vs 23%, P < 0.001, respectively). Moreover, the T1762/A1764 mutations in the BCP region in combination with either T1653 or A1896 were more common in the HCC compared with the CHB group (BCP+X1653: 18% vs 11%, P = 0.05; BCP+PC, 40% vs 15%, P < 0.001, respectively). In multivariate analysis, T1653 and A1896 were revealed to be independent risk factors for HCC development. G1896A in the precore region and C1653T mutation in the X region of genotype C2 HBV are important risk factors for HCC development. Also, the A1762T/G1764A double mutation may act in synergy with C1653T to increase the risk of HCC in patients chronically infected with HBV genotype C2.

Sphingoid bases from sea cucumber induce apoptosis in human hepatoma HepG2 cells through p-AKT and DR5

Biofunctional marine compounds have recently received substantial attention for their nutraceutical characteristics. In this study, we investigated the apoptosis-inducing effects of sphingoid bases prepared from sea cucumber using human hepatoma HepG2 cells. Apoptotic effects were determined by cell viability assay, DNA fragmentation assay, caspase-3 and caspase-8 activities. The expression levels of apoptosis-inducing death receptor-5 (DR5) and p-AKT were assayed by western blot analysis, and mRNA expression of bax, GADD45 and PPARγ was assayed by quantitative RT-PCR analysis. Sphingoid bases from sea cucumber markedly reduced the cell viability of HepG2 cells. DNA fragmentation indicative of apoptosis was observed in a dose-dependent manner. The expression levels of the apoptosis inducer protein Bax were increased by the sphingoid bases from sea cucumber. GADD45, which plays an important role in apoptosis-inducing pathways, was markedly upregulated by sphingoid bases from sea cucumber. Upregulation of PPARγ mRNA was also observed during apoptosis induced by the sphingoid bases. The expression levels of DR5 and p-AKT proteins were increased and decreased, respectively, as a result of the effects of sphingoid bases from sea cucumber. The results indicate that sphingoid bases from sea cucumber induce apoptosis in HepG2 cells through upregulation of DR5, Bax, GADD45 and PPARγ and downregulation of p-AKT. Our results show for the first time the functional properties of marine sphingoid bases as inducers of apoptosis in HepG2 cells.

Antiviral treatment to prevent chronic hepatitis B or C-related hepatocellular carcinoma

Antiviral treatment is the only option to prevent or defer the occurrence of hepatocellular carcinoma (HCC) in patients chronically infected with hepatitis B virus (HBV) or hepatitis C virus (HCV). The approved medication for the treatment of chronic HBV infection is interferon-α (IFNα) and nucleos(t)ide analogues (NAs), including lamivudine, adefovir dipivoxil, telbivudine, entecavir and tenofovir disoproxil fumarate. IFNα is the most suitable for young patients with less advanced liver diseases and those infected with HBV genotype A. IFNα treatment significantly decreases the overall incidence of HBV-related HCC in sustained responders. However, side effects may limit its long-term clinical application. Orally administered NAs are typically implemented for patients with more advanced liver diseases. NA treatment significantly reduces disease progression of cirrhosis and therefore HCC incidence, especially in HBV e antigen-positive patients. NA-resistance due to the mutations in HBV polymerase is a major limiting factor. Of the NA resistance-associated mutants, A181T mutant significantly increases the risk of HCC development during the subsequent course of NA therapy. It is important to initiate treatment with NAs that have a high genetic barrier to resistance, to counsel patients on medication adherence and to monitor virological breakthroughs. The recommended treatment for patients with chronic HCV infection is peg-IFN plus ribavirin that can decrease the occurrence of HCC in those who achieve a sustained virological response and have not yet progressed to cirrhosis. IFN-based treatment is reserved for patients with decompensated cirrhosis who are under evaluation of liver transplantation to reduce post-transplant recurrence of HCV. More effective therapeutic options such as direct acting antiviral agents will hopefully increase the response rate in difficult-to-treat patients with HCV genotype 1. However, the risk of HCC remains in cirrhotic patients (both chronic HBV and HCV infection) if treatment is initiated after cirrhosis is established. Future research should focus on investigating new agents, especially for those patients with hepatic decompensation or post-transplantation.

Effects of antiviral therapy on the recurrence of hepatocellular carcinoma after curative resection or liver transplantation

CONTEXT

Hepatocellular carcinoma (HCC) is a fatal disease. Chronic hepatitis B virus (HBV) and/or hepatitis C virus (HCV) infection is the major cause of HCC. High viral replication rate and related hepatic/systematic inflammation are the major risk factors in HCC recurrence after hepatectomy or liver transplantation.

EVIDENCE ACQUISITION

Some of the carcinogenesis-related HBV mutations are also associated with poor prognosis for HCC patients. Antiviral therapy is an option for improving HCC prognosis after surgery. In case of HBV-associated HCC, treatment with interferon and nucleos(t)ide analogues (NAs), especially interferon, is effective in improving the prognosis. However, long-term use of NAs increases the possibility of developing drug-resistant viral mutations such as the HBV rtA181T/sW172 mutation, which increases the risk of HCC recurrence.

RESULTS

In cases of HCV-associated HCC, standard interferon with or without ribavirin therapy is effective in improving the prognosis of HCV-associated HCC; however, some HCV mutations, such as the amino acid substitution M91L, are associated with treatment failure and a poor prognosis. Therapeutic efficacy needs to be confirmed using largescale, randomized, placebo-controlled clinical trials.

CONCLUSIONS

Surveillance of viral mutations during antiviral treatment and a better understanding of the associations of HCC recurrence with viral load, inflammation-associated signaling, and environmental factors can aid the development of more effective strategies for the prevention of HCC recurrence after surgery.

Challenges of incorporating gene expression data to predict HCC prognosis in the age of systems biology

Hepatocellular carcinoma (HCC) is a leading cause of cancer-related death worldwide. The recurrence of HCC after curative treatments is currently a major hurdle. Identification of subsets of patients with distinct prognosis provides an opportunity to tailor therapeutic approaches as well as to select the patients with specific sub-phenotypes for targeted therapy. Thus, the development of gene expression profiles to improve the prediction of HCC prognosis is important for HCC management. Although several gene signatures have been evaluated for the prediction of HCC prognosis, there is no consensus on the predictive power of these signatures. Using systematic approaches to evaluate these signatures and combine them with clinicopathologic information may provide more accurate prediction of HCC prognosis. Recently, Villanueva et al^[13] developed a composite prognostic model incorporating gene expression patterns in both tumor and adjacent tissues to predict HCC recurrence. In this commentary, we summarize the current progress in using gene signatures to predict HCC prognosis, and discuss the importance, existing issues and future research directions in this field.

Precore mutation of hepatitis B virus may contribute to hepatocellular carcinoma risk: evidence from an updated meta-analysis

Background

Studies focused on the correlation of mutations in the genome of Hepatitis B Virus (HBV) like Pre-S mutation, Basal Core promoter (BCP), Enhancer II (EnhII), especially Precore mutation, with the risk of hepatocellular carcinoma (HCC) have triggered stiff controversies. With an increasing number of studies in this field recently, we conducted this meta-analysis to appraise the correlations.

Methods

We searched the commonly used databases both in English and Chinese till February 1^st, 2012. Meta-analysis was performed in fixed/random-effects models using STATA 10.0. Publication bias was examined through Egger's test and Begg's funnel plot.

Results

In total, 85 case-control studies were included involving 16745 HBV-infected patients, of whom 5781 had HCC. Statistically significant correlations were observed in Precore mutation G1896A (OR = 1.46, 95% confidence interval [CI] = 1.15–1.85, P_OR = 0.002), G1899A (OR = 3.13, 95%CI = 2.38–4.13, P_OR<0.001) and Pre-S mutation especially Pre-S1 deletion (OR = 2.94, 95%CI = 2.22 to 3.89) and Pre-S2 deletion (OR = 3.02, 95%CI = 2.03 to 4.50). Similar correlation existed between BCP double mutation A1762T/G1764A, T1753V, C1653T and HCC. In subgroup analysis, the Asians, genotype C or HBeAg positive patients with certain above mutations may be more susceptible to HCC. Besides, the mutations like G1896A and BCP double mutation may be associated with the progression of the liver diseases.

Conclusions

Precore mutation G1896A, G1899A, deletions in Pre-S region as well as the other commonly seen mutations correlated with the increased risk of HCC, especially in Asians and may predict the progression of the liver disease.

Mutations within enhancer II and BCP regions of hepatitis B virus in relation to advanced liver diseases in patients infected with subgenotype B3 in Indonesia

Studies on the characteristics of mutations within the hepatitis B virus (HBV) genome, their roles in the pathogenesis of advanced liver diseases, and the involvement of host properties of HBV-infected individuals have not been conducted in subgenotype B3-infected populations. For addressing this issue, 40 cases with HBV surface antigen (HBsAg)-positive advanced liver diseases, including advanced liver cancer and cirrhosis (male 31, female 9, age 54.4 ± 11.6-year-old), were collected and compared with 109 cases with chronic hepatitis B (male 71, female 38, age 38.0 ± 13.4-year-old). Mutations in enhancer II (Enh II) and basal core promoter (BCP)/precore regions were analyzed by PCR-direct sequencing method. HBV viral load was examined by real-time PCR. For all examined regions, the prevalence of mutation was significantly higher in cases with advanced liver diseases. Multivariate analysis showed that, in patients older than 45 years, C1638T and T1753V mutations constituted independent risk factors for the advancement of liver diseases. The presence of C1638T and T1753V mutations may serve as predictive markers for the progression of liver diseases in Indonesia and other countries, where subgenotype B3 infection is prevalent.

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 Th1 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.

Predictive power of hepatitis B 1762T/1764A mutations in plasma for hepatocellular carcinoma risk in Qidong, China

Hepatocellular carcinoma (HCC) is a leading cause of cancer mortality with nearly 700,000 deaths occurring annually. Hepatitis B virus (HBV) is a major contributor to HCC and acquired mutations in the HBV genome may accelerate its pathogenesis. In this study, a matched case-control investigation of 345 men who died of HCC and 625 controls were nested within a cohort of male hepatitis B surface antigen (HBsAg) carriers from Qidong, China. Matched preserving odds ratios (ORs) were used as a measure of association and 95% confidence intervals (CIs) as a measure of precision. Real-time polymerase chain reaction allowed for a quantitative comparison of the levels of the HBV 1762(T)/1764(A) mutation in cases and controls. A total of 278 (81%) of the cases were positive for the HBV 1762(T)/1764(A) mutation compared with 250 (40%) of the controls. The matched preserving OR of 6.72 (95% CI: 4.66 to 9.68) strongly indicated that cases were significantly more probably than controls to have the mutation. Plasma levels of DNA harboring the HBV mutation were on average 15-fold higher in cases compared with controls (P < 0.001). Most strikingly, the level of the mutation in the 20 controls who later developed and died of HCC were on average 274-fold higher than controls who did not develop HCC. Thus, within this cohort of HBsAg carriers at high risk of developing HCC, individuals positive for the HBV 1762(T)/1764(A) mutation at enrollment were substantially more probably to subsequently develop HCC, with a higher concentration of the mutation in plasma enhancing predisposition for cancer development.

Update on the Risk of Hepatocellular Carcinoma in Chronic Hepatitis B Virus Infection

Chronic hepatitis B virus infection is an important cause of liver-related morbidity and mortality, with hepatocellular carcinoma being the most life-threatening complication. Because of the highly variable clinical course of the disease, enormous research efforts have been made with the aim of revealing the factors in the natural history that are relevant to hepatocarcinogenesis. These include epidemiological studies of predisposing risk groups, viral studies of mutations within the hepatitis B viral genome, and clinical correlation of these risk factors in predicting the likelihood of development of hepatocellular cancer in susceptible hosts. This update addresses these risks, with emphasis on the latest research relevant to hepatocarcinogenesis.

Update on the Risk of Hepatocellular Carcinoma in Chronic Hepatitis B Virus Infection

Chronic hepatitis B virus infection is an important cause of liver-related morbidity and mortality, with hepatocellular carcinoma being the most life-threatening complication. Because of the highly variable clinical course of the disease, enormous research efforts have been made with the aim of revealing the factors in the natural history that are relevant to hepatocarcinogenesis. These include epidemiological studies of predisposing risk groups, viral studies of mutations within the hepatitis B viral genome, and clinical correlation of these risk factors in predicting the likelihood of development of hepatocellular cancer in susceptible hosts. This update addresses these risks, with emphasis on the latest research relevant to hepatocarcinogenesis.