Clinical features of hepatitis B virus-related hepatocellular carcinoma

The role of the hepatitis B virus genome and its integration in the hepatocellular carcinoma

The integration of Hepatitis B Virus (HBV) is now known to be closely associated with the occurrence of liver cancer and can impact the functionality of liver cells through multiple dimensions. However, despite the detailed understanding of the characteristics of HBV integration and the mechanisms involved, the subsequent effects on cellular function are still poorly understood in current research. This study first systematically discusses the relationship between HBV integration and the occurrence of liver cancer, and then analyzes the status of the viral genome produced by HBV replication, highlighting the close relationship and structure between double-stranded linear (DSL)-HBV DNA and the occurrence of viral integration. The integration of DSL-HBV DNA leads to a certain preference for HBV integration itself. Additionally, exploration of HBV integration hotspots reveals obvious hotspot areas of HBV integration on the human genome. Virus integration in these hotspot areas is often associated with the occurrence and development of liver cancer, and it has been determined that HBV integration can promote the occurrence of cancer by inducing genome instability and other aspects. Furthermore, a comprehensive study of viral integration explored the mechanisms of viral integration and the internal integration mode, discovering that HBV integration may form extrachromosomal DNA (ecDNA), which exists outside the chromosome and can integrate into the chromosome under certain conditions. The prospect of HBV integration as a biomarker was also probed, with the expectation that combining HBV integration research with CRISPR technology will vigorously promote the progress of HBV integration research in the future. In summary, exploring the characteristics and mechanisms in HBV integration holds significant importance for an in-depth comprehension of viral integration.

Antiviral Therapy Improves Survival in Hepatocellular Carcinoma with Microvascular Invasion: A Propensity Score Analysis

BACKGROUND AND AIMS

To investigate the effect of postoperative adjuvant antiviral therapy (AVT) on hepatitis B virus (HBV) related hepatocellular carcinoma (HCC) with microvascular invasion (MVI) after R0 liver resection.

METHODS

A total of 1008 patients with HBV-related HCC with MVI were recruited, which comprises 378 non-AVT groups and 630 AVT groups. Propensity score matching (PSM) was developed to reduce any bias in patient selection. Independent risk factors were identified by Cox regression analysis.

RESULTS

After PSM, the 1-, 3-, and 5-year overall survival rates in the AVT group and non-AVT group were 89.2%, 62.4%, 42.1%, and 73.3%, 46.3%, 22.1%, (p < 0.01), respectively. The 1-, 3-, and 5-year recurrence-free survival rates in the AVT group and non-AVT group were 52.5%, 30.4%, 22.1%, and 46.3%, 26.8%, 13.2% (p = 0.02), respectively. Multivariate Cox analysis revealed that postoperative adjuvant AVT was the independent protective factor associated with mortality (HR = 0.55, 95%CI = 0.46-0.67, p < 0.01) and tumor recurrence (HR = 0.81, 95%CI = 0.69-0.96, p = 0.01).

CONCLUSIONS

Among patients who underwent curative hepatectomy for HBV-related HCC with MVI, postoperative adjuvant AVT was the independent protective factor associated with mortality and tumor recurrence. Given the high rate of postoperative recurrence and poor prognosis of HBV-related HCC with MVI, our findings may have useful clinical significance in the prevention of tumor recurrence in these patients.

Outcomes of adolescent and young patients with hepatocellular carcinoma after curative liver resection: a retrospective study

BACKGROUND

The risk of HCC is documented to be age-related. The outcomes of young HCC patients on postoperative prognosis are not well understood. The study aims to compare the characteristic differences between adolescent and young (AYA) and non-AYA HCC patients.

METHODS

We performed a retrospective analysis of the clinical and pathological findings and the survival of 243 HCC patients who underwent operations between 2007 and 2018.

RESULTS

The AYA group had a higher AFP level and a higher prevalence of family history of HCC or other cancers than the non-AYA group (P < 0.01 and P < 0.05). AYA patients had more unfavorable pathological characteristics including bigger lesion size, microvascular invasion, portal vein invasion, and hepatic capsule invasion. They also had a more unfavorable Edmondson grade and less tumor capsule formation (P < 0.01). Age was an independent predictor of survival in HCC patients. AYA patients had poorer disease-free and overall survival than non-AYA patients did (P < 0.01). Patients under 30 years old had an even poorer disease-free survival than those aged 30-40 (P = 0.047).

CONCLUSIONS

AYA patients exhibited a higher recurrence rate and disease-related death rate with more unfavorable pathological characteristics. Enhanced follow-up for young HCC patients should be applied.

HBV genome-enriched single cell sequencing revealed heterogeneity in HBV-driven hepatocellular carcinoma (HCC)

BACKGROUND

Hepatitis B virus (HBV) related hepatocellular carcinoma (HCC) is heterogeneous and frequently contains multifocal tumors, but how the multifocal tumors relate to each other in terms of HBV integration and other genomic patterns is not clear.

METHODS

To interrogate heterogeneity of HBV-HCC, we developed a HBV genome enriched single cell sequencing (HGE-scSeq) procedure and a computational method to identify HBV integration sites and infer DNA copy number variations (CNVs).

RESULTS

We performed HGE-scSeq on 269 cells from four tumor sites and two tumor thrombi of a HBV-HCC patient. HBV integrations were identified in 142 out of 269 (53%) cells sequenced, and were enriched in two HBV integration hotspots chr1:34,397,059 (CSMD2) and chr8:118,557,327 (MED30/EXT1). There were also 162 rare integration sites. HBV integration sites were enriched in DNA fragile sites and sequences around HBV integration sites were enriched for microhomologous sequences between human and HBV genomes. CNVs were inferred for each individual cell and cells were grouped into four clonal groups based on their CNVs. Cells in different clonal groups had different degrees of HBV integration heterogeneity. All of 269 cells carried chromosome 1q amplification, a recurrent feature of HCC tumors, suggesting that 1q amplification occurred before HBV integration events in this case study. Further, we performed simulation studies to demonstrate that the sequential events (HBV infecting transformed cells) could result in the observed phenotype with biologically reasonable parameters.

CONCLUSION

Our HGE-scSeq data reveals high heterogeneity of HCC tumor cells in terms of both HBV integrations and CNVs. There were two HBV integration hotspots across cells, and cells from multiple tumor sites shared some HBV integration and CNV patterns.

OUP accepted manuscript

Background

Methods

Results

Conclusion

Long-read sequencing reveals the structural complexity of genomic integration of HBV DNA in hepatocellular carcinoma

The integration of HBV DNA into the human genome can disrupt its structure in hepatocellular carcinoma (HCC), but the complexity of HBV genomic integration remains elusive. Here we applied long-read sequencing to precisely elucidate the HBV integration pattern in the human hepatocellular genome. The DNA library was sequenced using the long-read sequencing on GridION and PacBio Sequel II, respectively. The DNA and mRNA were sequenced using next-generation sequencing on Illumina NextSeq. BLAST (Basic Local Alignment Search Tool) and local scripts were used to analyze HBV integration patterns. We established an analytical strategy based on the long-read sequences, and analyzed the complexity of HBV DNA integration into the hepatocellular genome. A total of 88 integrated breakpoints were identified. HBV DNA integration into human genomic DNA was mainly fragmented with different orientations, rarely with a complete genome. The same HBV integration breakpoints were identified among the three platforms. Most breakpoints were observed at P, X, and S genes in the HBV genome, and observed at introns, intergenic sequences, and exons in the human genome. Tumor tissue harbored a much higher integrated number than the adjacent tissue, and the distribution of HBV integrated into human chromosomes was more concentrated. HBV integration shows different patterns between cancer cells and adjacent normal cells. We for the first time obtained the entire HBV integration pattern through long-read sequencing and demonstrated the value of long-read sequencing in detecting the genomic integration structures of viruses in host cells.

Adenovirus Vectors Expressing Eight Multiplex Guide RNAs of CRISPR/Cas9 Efficiently Disrupted Diverse Hepatitis B Virus Gene Derived from Heterogeneous Patient

Hepatitis B virus (HBV) chronically infects more than 240 million people worldwide, causing chronic hepatitis, cirrhosis, and hepatocellular carcinoma (HCC). Genome editing using CRISPR/Cas9 could provide new therapies because it can directly disrupt HBV genomes. However, because HBV genome sequences are highly diverse, the identical target sequence of guide RNA (gRNA), 20 nucleotides in length, is not necessarily present intact in the target HBV DNA in heterogeneous patients. Consequently, possible genome-editing drugs would be effective only for limited numbers of patients. Here, we show that an adenovirus vector (AdV) bearing eight multiplex gRNA expression units could be constructed in one step and amplified to a level sufficient for in vivo study with lack of deletion. Using this AdV, HBV X gene integrated in HepG2 cell chromosome derived from a heterogeneous patient was cleaved at multiple sites and disrupted. Indeed, four targets out of eight could not be cleaved due to sequence mismatches, but the remaining four targets were cleaved, producing irreversible deletions. Accordingly, the diverse X gene was disrupted at more than 90% efficiency. AdV containing eight multiplex gRNA units not only offers multiple knockouts of genes, but could also solve the problems of heterogeneous targets and escape mutants in genome-editing therapy.

Studies on the correlation between mutation and integration of HBV in hepatocellular carcinoma

It is well known that both the mutation and integration of the Hepatitis B virus (HBV) are of great significance in liver cancer, however, the relationship between mutation and integration is still unclear. In the present study, sequencing data from 426 previously published samples were analyzed and 5374 specific HBV mutations in cancer tissues were discovered. By comparing integrated samples and non-integrated samples, we found that the integrated samples had higher sample single nucleotide variants (SNVs) positive rates and SNV numbers, as well as higher sample frequency of SNV in the X region of the HBV genome. Samples with HBV integration in the telomerase reverse transcriptase (TERT) region showed higher SNV positive rates and numbers than samples without integration. Moreover, the SNVs (209 [T>G] and 531 [T>C; T>G]) were seen with higher frequency in samples with integration in the TERT region. Our study showed that the occurrence of viral integration events is closely related to the occurrence of SNV, and SNV in the X region should be more directly associated with viral integration. The present study provides an initial exploration of the relationship between HBV mutation and integration to help improve our understanding of the relationship between viral integration and mutation.

Profile of different Hepatitis B virus integration frequency in hepatocellular carcinoma patients

Hepatitis B virus (HBV) DNA integration is closely related to the occurrence of liver cancer. However, current studies mostly focus on the detection of the viral integration sites, ignoring the relationship between the frequency of viral integration and liver cancer. Thus, this study uses previous data to distinguish the breakpoints according to the integration frequency and analyzes the characteristics of different groups. This analysis revealed that three sets of breakpoints were characterized by its own integrated sample frequency, breakpoint distribution, and affected gene pathways. This result indicated an evolution in the virus integration sites in the process of tumor formation and development. Therefore, our research clarified the characteristics and differences in the sites of viral integration in tumors and adjacent tissues, and clarified the key signaling pathways affected by viral integration. Hence, these findings might be of great significance in the understanding of the role of viral integration frequency in hepatocellular carcinoma.

C-terminal truncated HBx initiates hepatocarcinogenesis by downregulating TXNIP and reprogramming glucose metabolism

Chronic hepatitis B virus (HBV) infection is strongly associated with the initiation and development of hepatocellular carcinoma (HCC). However, the genetic alterations and pathogenesis mechanisms remain significantly unexplored, especially for HBV-induced metabolic reprogramming. Analysis of integration breakpoints in HBV-positive HCC samples revealed the preferential clustering pattern within the 3′-end of X gene in the HBV genome, leading to the production of C-terminal truncated X protein (Ct-HBx). In this study, we not only characterized the oncogenic role of two Ct-HBx (HBx-120 and HBx-134) via in vitro and in vivo functional assays but also deciphered their underlying molecular mechanisms. Gene expression profiling by transcriptome sequencing identified potential targets of Ct-HBx and novel malignant hallmarks such as glycolysis, cell cycle, and m-TORC1 signaling in Ct-HBx-expressing cells. TXNIP, a well-established regulator of glucose metabolism, was shown to be downregulated by Ct-HBx and play a pivotal role in Ct-HBx-mediated HCC progression. Suppression of TXNIP is frequently observed in HCC patients with Ct-HBx expression and significantly (P = 0.015) correlated to a poorer prognosis. Re-introduction of TXNIP attenuated the metabolic reprogramming induced by the Ct-HBx and inhibited the tumor growth in the mice model. Further study suggested that Ct-HBx could downregulate TXNIP via a transcriptional repressor nuclear factor of activated T cells 2 (NFACT2). Collectively, our findings indicate that TXNIP plays a critical role in Ct-HBx-mediated hepatocarcinogenesis, serving as a novel therapeutic strategy in HCC treatment.

Prognosis Factors of Young Patients Undergoing Curative Resection for Hepatitis B Virus-Related Hepatocellular Carcinoma: A Multicenter Study

Background

The prognosis of young and older patients with hepatocellular carcinoma (HCC) is controversial. We aim to compare the clinicopathological features and prognosis of young (age ≤40 years) versus older patients (aged >40 years) with hepatitis B virus (HBV)-related HCC after curative resection.

Methods

A total of 4504 patients with HBV-related HCC who underwent curative resection were included in this study and divided into young group (n=699) and older group (n=3805). Subgroup analyses were conducted to compare. Independent risk factors were identified by Cox regression analysis.

Results

Young patients had better ALBI grade, lower rates of liver cirrhosis, higher rates of elevated serum AFP levels, larger tumor size, higher rates of microvascular invasion and macrovascular invasion, higher rates of Edmondson grade III–IV, lower rates of tumor capsular, more advanced AJCC TNM stages and more advanced BCLC stages than older patients (All p<0.05). Meanwhile, young patients had a worse overall survival (OS) rate (p=0.0091) and a worse recurrence-free survival (RFS) rate (p=0.045) than older patients. Multivariate analysis revealed that AFP, resection margin, tumor size, tumor capsular, and macrovascular invasion were associated with OS. The independent risk factors associated with RFS were ALB, tumor size, microvascular invasion, and macrovascular invasion.

Conclusion

Young patients had better liver function, more aggressive tumor characteristics, and worse prognosis than older patients. A tumor size of ≥5 cm and macrovascular invasion were associated with poor OS and RFS in young patients. If tumors could be detected at the early stage by more frequent surveillance, long-term survival can be expected in the young patients.

Multiple novel hepatocellular carcinoma signature genes are commonly controlled by the master pluripotency factor OCT4

BACKGROUND

Worldwide, hepatocellular carcinoma (HCC) is a common solid tumor with a poor prognosis. HCC is often due to hepatitis B virus (HBV) infection. As yet, efficacious HCC treatment regimens for late-stage HCC patients are lacking. Therefore, the identification of more specific and sensitive biomarkers for its early diagnosis and treatment remains an urgent need.

METHODS

Total RNAs from paired HBV-derived HCC tumors and adjacent peritumor tissues (APTs) were subjected to RNA sequencing (RNA-seq), and differentially expressed genes (DEGs) between HCC tumors and APTs were selected and verified.

RESULTS

We identified 166 DEGs and found that eight top-ranked and verified DEGs (TK1, CTTN, CEP72, TRIP13, FTH1, FLAD1, CHRM2, AMBP) all contained putative OCT4 binding motifs in their promoter regions. TK1, TRIP13 and OCT4 were found to exhibit concurrent higher expression levels in HCC tumors than in APTs. The mRNA levels of TK1, TRIP13 and OCT4 in a cohort of 384 HCC samples from the TCGA database were all found to be negatively correlated with patient overall survival, relapse-free survival and progression-free survival, underscoring the HCC biomarker status of TK1 and TRIP13 on one hand, and implicating their association with OCT4 on the other hand. Furthermore, OCT4 proteins were found to bind to the promoters of both genes in vitro and in vivo. Knocking out OCT4 in HCC-derived cell lines reduced the expression of TK1 and TRIP13 and significantly decreased their tumorigenicity.

CONCLUSIONS

Using RNA-seq, we identified several novel HCC signature genes that may serve as biomarkers for its diagnosis and prognosis. Their common transcriptional regulation by OCT4 suggests key roles in the development of HCC, and indicates that OCT4 may serve as a potential therapeutic target.

Natural regression of fibrosis in chronic hepatitis B

The fibrosis of liver cirrhosis was considered to be irreversible before the anti-viral drugs showed that it is reversible when they lead to continuous suppression of viral replication and inflammation. However, several reports previously showed that fibrosis of type B liver cirrhosis was almost completely absorbed after the natural remission of chronic inflammation. This phenomenon might not be limited to exceptional patients, but rather occur commonly, considering the dynamic clinical features of chronic hepatitis B (CHB), where inactive carrier stage normally follows aggravation of hepatitis and progression of fibrosis at the time of HBeAg seroconversion. Thus, fibrosis levels of CHB as a hepatocellular carcinoma (HCC)-surveillance marker, particularly those of the inactive stage, could be underestimated, because some of them might have been (pre)cirrhotic in the past and recovered with the natural regression of fibrosis. We argue that cirrhosis-induced HCC mechanisms, rather than direct action of viral genome, may be more common than generally considered in CHB patients. This may have some impact on reconsidering the surveillance rationale for HCC in CHB, from where advanced HCCs tended to be missed. In addition, a molecular marker to assess the cancer-prone characteristics of the liver will definitely be needed to resolve the issue.

Novel pre-mRNA splicing of intronically integrated HBV generates oncogenic chimera in hepatocellular carcinoma

BACKGROUND & AIMS

Hepatitis B virus (HBV) integration is common in HBV-associated hepatocellular carcinoma (HCC) and may play an important pathogenic role through the production of chimeric HBV-human transcripts. We aimed to screen the transcriptome for HBV integrations in HCCs.

METHODS

Transcriptome sequencing was performed on paired HBV-associated HCCs and corresponding non-tumorous liver tissues to identify viral-human chimeric sites. Validation was further performed in an expanded cohort of human HCCs.

RESULTS

Here we report the discovery of a novel pre-mRNA splicing mechanism in generating HBV-human chimeric protein. This mechanism was exemplified by the formation of a recurrent HBV-cyclin A2 (CCNA2) chimeric transcript (A2S), as detected in 12.5% (6 of 48) of HCC patients, but in none of the 22 non-HCC HBV-associated cirrhotic liver samples examined. Upon the integration of HBV into the intron of the CCNA2 gene, the mammalian splicing machinery utilized the foreign splice sites at 282nt. and 458nt. of the HBV genome to generate a pseudo-exon, forming an in-frame chimeric fusion with CCNA2. The A2S chimeric protein gained a non-degradable property and promoted cell cycle progression, demonstrating its potential oncogenic functions.

CONCLUSIONS

A pre-mRNA splicing mechanism is involved in the formation of HBV-human chimeric proteins. This represents a novel and possibly common mechanism underlying the formation of HBV-human chimeric transcripts from intronically integrated HBV genome with functional impact.

LAY SUMMARY

HBV is involved in the mammalian pre-mRNA splicing machinery in the generation of potential tumorigenic HBV-human chimeras. This study also provided insight on the impact of intronic HBV integration with the gain of splice sites in the development of HBV-associated HCC.

Characterization of the genotype and integration patterns of hepatitis B virus in early- and late-onset hepatocellular carcinoma

Early-onset hepatocellular carcinoma (HCC) accounts for 15%-20% of total HCC cases in Asia, and the incidence is increasing. The low frequency of cirrhosis and poor prognosis of early-onset HCC suggests that its mechanisms may differ from late-onset HCC. Although hepatitis B virus (HBV) infection is epidemiologically associated with HCC, the role of HBV in early-onset HCC remains poorly understood. Here, we report a comparative study of HBV subgenotypes and integration in early- (≤30) and late-onset (≥70) HBV-associated HCC using a novel high-throughput viral integration detection method. We report that HBV B2 is predominantly present in early-onset HCC. HBV integration is a common phenomenon, both in early- and late-onset HCC, which favors integrating into human repeat regions. Moreover, we found a breakpoint in 8q24 located between c-Myc and plasmocytoma variant translocation 1 (PVT1), which was detected in 12.4% (14 of 113) of early-onset HCCs, but only 1.4% (2 of 145) in late-onset HCCs. HBV integrating this site results in c-MYC, PVT1, and microRNA-1204 overexpression in tumors, thereby potentially contributing to the development of early-onset HCC.

CONCLUSION

HBV genotype and integration patterns may be distinct in early-onset HCC. Our results may shed light on HCC risk factors in young HBV carriers. Further studies are needed to elucidate at which time in tumor development this integration event occurs and whether it plays an important, causative role in HCC development or progression.

Dr.VIS v2.0: an updated database of human disease-related viral integration sites in the era of high-throughput deep sequencing

Dr.VIS is a database of human disease-related viral integration sites (VIS). The number of VIS has grown rapidly since Dr.VIS was first released in 2011, and there is growing recognition of the important role that viral integration plays in the development of malignancies. The updated database version, Dr.VIS v2.0 (http://www.bioinfo.org/drvis or bminfor.tongji.edu.cn/drvis_v2), represents 25 diseases, covers 3340 integration sites of eight oncogenic viruses in human chromosomes and provides more accurate information about VIS from high-throughput deep sequencing results obtained mainly after 2012. Data of VISes for three newly identified oncogenic viruses for 14 related diseases have been added to this 2015 update, which has a 5-fold increase of VISes compared to Dr.VIS v1.0. Dr.VIS v2.0 has 2244 precise integration sites, 867 integration regions and 551 junction sequences. A total of 2295 integration sites are located near 1730 involved genes. Of the VISes, 1153 are detected in the exons or introns of genes, with 294 located up to 5 kb and a further 112 located up to 10 kb away. As viral integration may alter chromosome stability and gene expression levels, characterizing VISes will contribute toward the discovery of novel oncogenes, tumor suppressor genes and tumor-associated pathways.

Hepatitis B Virus-Related Hepatocellular Carcinoma: Pathogenic Mechanisms and Novel Therapeutic Interventions

BACKGROUND

Infection with the hepatitis B virus (HBV) is one of most important risk factors for hepatocellular carcinoma (HCC). Indeed, HBV is considered a group 1 human carcinogen and is a highly oncogenic agent. HBV cannot be effectively controlled or completely eliminated, so chronic HBV infection is a public health challenge worldwide.

SUMMARY

It is now believed that HBV-induced HCC involves a complex interaction between multiple viral and host factors. Many factors contribute to HBV-associated HCC, including products of HBV, viral integration and mutation, and host susceptibility. This review outlines the main pathogenic mechanisms with a focus on those that suggest novel targets for the prevention and treatment of HCC.

KEY MESSAGE

HBV infection is an important risk factor for HCC. Understanding the interaction between viral and host factors in HBV-induced HCC will reveal potential targets for future therapies.

PRACTICAL IMPLICATIONS

The two main therapeutic strategies consist of antiviral agents and immunotherapy-based approaches. Dendritic cell-based immunotherapy is promising for restoring the T cell-mediated antiviral immune response. Another approach is the specific expansion of the host's pool of HBV-specific T cells. Stimulation of the Toll-like receptors (TLRs), particularly TLR9, provides another means of boosting the antiviral response. Combination therapy with cytokines (interferon gamma and tumor necrosis factor alpha) plus lamivudine is more effective than these agents used alone. Therapeutic vaccines are being developed as an alternative to long-term antiviral treatment or as an adjunct.

Dynamic multidetector computed tomography findings of hepatocellular carcinoma of hepatitis B virus-positive and -negative patients

Background

The objective of this study was to retrospectively investigate and compare multidetector computed tomography findings of hepatocellular carcinoma (HCC) in hepatitis B virus (HBV)-positive and -negative patients.

Methods

Triphasic (arterial, portal venous, and delayed phases) dynamic multidetector computed tomography (CT) was performed in 83 patients with HCC, 48 of whom were HBV-positive. The diagnosis of HCC was established with typical CT imaging findings (68 patients) or histopathological evaluation (15 patients). Distribution of solitary, multiple, and diffuse HCC, portal/hepatic vein thrombosis, metastasis, and patients with high alpha-fetoprotein levels in the HBV-positive and -negative groups were compared using the Kolmogorov–Smirnov test. Lesion size, alpha-fetoprotein levels, arterial, portal, delayed enhancement, and washout of lesions were compared using the Student’s t-test.

Results

Hypervascular tumors were observed in 72 (87%) patients, and hypovascular tumors were found in 11 (13%) patients. The mean alpha-fetoprotein value of HBV-positive patients with HCC was significantly higher than the mean alpha-fetoprotein value of HBV-negative patients (P < 0.05). Portal/hepatic vein thrombosis and metastasis were more frequently observed in HBV-positive patients (P < 0.05). The frequencies of solitary, multiple, and diffuse lesions in HBV-positive and -negative patients were not significantly different (P > 0.05). The mean diameters, arterial, portal, and delayed phase attenuations, and washout of HCC were not significantly different (P > 0.05).

Conclusions

Multidetector CT imaging findings of HCC in HBV-positive and -negative patients are alike. Portal/hepatic vein thrombosis and metastasis are more frequently observed in HBV-positive patients. Alpha-fetoprotein levels are higher in HBV-positive patients.

Tackling hepatitis B virus-associated hepatocellular carcinoma--the future is now

Hepatocellular carcinoma (HCC) is one of the most lethal and prevalent cancers in many developing countries including India. Among the various etiological factors being implicated in the cause of HCC, the most important cause, however, is hepatitis B virus (HBV) infection. Among all HBV genes, HBx is the most critical carcinogenic component, the molecular mechanisms of which have not been completely elucidated. Despite its clinical significance, there exists a very elemental understanding of the molecular, cellular, and environmental mechanisms that drive disease pathogenesis in HCC infected with HBV. Furthermore, there are only limited therapeutic options, the clinical benefits of which are insignificant. Therefore, the quest for novel and effective therapeutic regimen against HBV-related HCC is of paramount importance. This review attempts to epitomize the current state of knowledge of this most common and dreaded liver neoplasm, highlighting the putative treatment avenues and therapeutic research strategies that need to be implemented with immediate effect for tackling HBV-related HCC that has plagued the medical and scientific fraternity for decades. Additionally, this review proposes a novel "five-point" management algorithm for HBV-related HCC apart from portraying the unmet needs, principal challenges, and scientific perspectives that are relevant to controlling this accelerating global health crisis.

HIVID: an efficient method to detect HBV integration using low coverage sequencing

We reported HIVID (high-throughput Viral Integration Detection), a novel experimental and computational method to detect the location of Hepatitis B Virus (HBV) integration breakpoints in Hepatocellular Carcinoma (HCC) genome. In this method, the fragments with HBV sequence were enriched by a set of HBV probes and then processed to high-throughput sequencing. In order to evaluate the performance of HIVID, we compared the results of HIVID with that of whole genome sequencing method (WGS) in 28 HCC tumors. We detected a total of 246 HBV integration breakpoints in HCC genome, 113 out of which were within 400bp upstream or downstream of 125 breakpoints identified by WGS method, covering 89.3% (125/140) of total breakpoints. The integration was located in the gene TERT, MLL4, and CCNE1. In addition, we discovered 133 novel breakpoints missed by WGS method, with 66.7% (10/15) of validation rate. Our study shows HIVID is a cost-effective methodology with high specificity and sensitivity to identify viral integration in human genome.

Association between hepatitis B or hepatitis C virus infection and risk of pancreatic adenocarcinoma development: a systematic review and meta-analysis

BACKGROUND

Pancreatic adenocarcinoma (PAC) is an aggressive cancer with a poor prognosis. To date, PAC causes are still largely unknown. Antigens and replicative sequences of oncogenic hepatitis B (HBV) and hepatitis C (HCV) virus were detected in different extra-hepatic tissues, including pancreas.

OBJECTIVE

a systematic review and meta-analysis of epidemiological studies assessing PAC risk in patients with HBV/HCV chronic infections.

METHODS

In September 2012, we extracted the articles published in Medline, Embase and the Cochrane Library, using the following search terms: "chronic HBV" and "HCV", "hepatitis", "PAC", "risk factors", "epidemiology". Only case/control (C/C), prospective/retrospective cohort studies (PCS/RCS) written in English were collected.

RESULTS

four hospital-based C/C studies and one PCS, in HBV-infected patients and two hospital-based C/C studies and one RCS in HCV-infected subjects met inclusion criteria. In these studies HBsAg positivity enhanced significantly PAC risk (RR = 1.18, 95% CI:1.04-1.33), whereas HBeAg positivity (RR = 1.31, 95% CI:0.85-2.02) as well as HBsAg negative/HBcAb positive/HBsAb positive pattern (RR = 1.12, 95% CI:0.78-1.59) and HBsAg negative/HBcAb positive/HBsAb negative pattern (RR = 1.30, 95% CI:0.93-1.84) did not. Relationship between PAC risk and anti-HCV positivity was not significant, although it reached a borderline value (RR = 1.160, 95% CI:0.99-1.3).

CONCLUSIONS

HBV/HCV infection may represent a risk factor for PAC, but the small number of available researches, involving mainly populations of Asian ethnicity and the substantial variation between different geographical areas in seroprevalence of HBV/HCV-antigens/antibodies and genotypes are limiting factors to present meta-analysis.

Hepatitis B virus gene mutations and hepatocarcinogenesis

Chronic hepatitis B virus (HBV) infection has long been the most common cause of hepatocellular carcinoma (HCC). However, some aspects of the pathogenesis of HBV infection and genesis of hepatitis B virus (HBV)-related hepatocellular carcinoma (HCC) are still inconclusive. An increasing number of published studies indicate that hepatitis B virus mutations are associated with risk of HCC. These variations include, in particular, mutations in ORF S,C,X gene regions. This mini-review summarizes results of clinical studies and molecular mechanisms on the possible relations of HBV mutations with the development of hepatocellular carcinoma.

Hepatitis B and C virus infections as possible risk factor for pancreatic adenocarcinoma

Pancreatic adenocarcinoma (PAC) is a very aggressive and lethal cancer, with a very poor prognosis, because of absence of early symptoms, advanced stage at presentation, early metastatic dissemination and lack of both specific tests to detect its growth in the initial phases and effective systemic therapies. To date, the causes of PAC still remain largely unknown, but multiple lines of evidence from epidemiological and laboratory researches suggest that about 15-20% of all cancers are linked in some way to chronic infection, in particular it has been shown that several viruses have a role in human carcinogenesis. The purpose of this report is to discuss the hypothesis that two well-known oncogenic viruses, Human B hepatitis (HBV) and Human C hepatitis (HCV) are a possible risk factor for this cancer. Therefore, with the aim to examine the potential link between these viruses and PAC, we performed a selection of observational studies evaluating this association and we hypothesized that some pathogenetic mechanisms involved in liver carcinogenesis might be in common with pancreatic cancer development in patients with serum markers of present or past HBV and HCV infections. To date the available observational studies performed are few, heterogeneous in design as well as in end-points and with not univocal results, nevertheless they might represent the starting-point for future larger and better designed clinical trials to define this hypothesized relationship. Should these further studies confirm an association between HBV/HCV infection and PAC, screening programs might be justified in patients with active or previous hepatitis B and C viral infection.

Genome-wide survey of recurrent HBV integration in hepatocellular carcinoma

To survey hepatitis B virus (HBV) integration in liver cancer genomes, we conducted massively parallel sequencing of 81 HBV-positive and 7 HBV-negative hepatocellular carcinomas (HCCs) and adjacent normal tissues. We found that HBV integration is observed more frequently in the tumors (86.4%) than in adjacent liver tissues (30.7%). Copy-number variations (CNVs) were significantly increased at HBV breakpoint locations where chromosomal instability was likely induced. Approximately 40% of HBV breakpoints within the HBV genome were located within a 1,800-bp region where the viral enhancer, X gene and core gene are located. We also identified recurrent HBV integration events (in ≥ 4 HCCs) that were validated by RNA sequencing (RNA-seq) and Sanger sequencing at the known and putative cancer-related TERT, MLL4 and CCNE1 genes, which showed upregulated gene expression in tumor versus normal tissue. We also report evidence that suggests that the number of HBV integrations is associated with patient survival.

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.

Genotypes, mutations, and viral load of hepatitis B virus and the risk of hepatocellular carcinoma: HBV properties and hepatocarcinogenesis

Chronic infection with hepatitis B virus (HBV) is the major risk factor for hepatocellular carcinoma (HCC) worldwide. Ten HBV genotypes (A-J) have been discovered so far. Genotypes B and C are endemic in East and Southeast Asia. Genotype C HBV is associated with increased risks of cirrhosis and HCC. Genotype B (B2) is associated with the development of HCC in non-cirrhotic patients younger than 50 years and with relapse of HCC after surgical treatment. It is also associated with earlier hepatitis B e antigen seroconversion than genotype C. High HBV load is independently associated with the occurrence and post-treatment recurrence of HCC. Different genotypes have distinct patterns of mutations. Viral mutations in the core promoter region and in the preS region are frequently found to be significantly associated with an increased risk of HCC. These mutations often occur before the onset of HCC and accumulate during the progression of chronic HBV infection. Multiple such mutations are more frequent in patients with HCC and are specific for HCC. HBV subgenotypes, viral mutations, and viral load can be used for the prediction of HCC. Early identification of HBV-infected individuals who will eventually develop HCC will help to develop active prophylactic protocols to reduce or delay the occurrence of HCC.

Gene set enrichment analysis of microarray data from Pimephales promelas (Rafinesque), a non-mammalian model organism

Background

Methods for gene-class testing, such as Gene Set Enrichment Analysis (GSEA), incorporate biological knowledge into the analysis and interpretation of microarray data by comparing gene expression patterns to pathways, systems and emergent phenotypes. However, to use GSEA to its full capability with non-mammalian model organisms, a microarray platform must be annotated with human gene symbols. Doing so enables the ability to relate a model organism's gene expression, in response to a given treatment, to potential human health consequences of that treatment. We enhanced the annotation of a microarray platform from a non-mammalian model organism, and then used the GSEA approach in a reanalysis of a study examining the biological significance of acute and chronic methylmercury exposure on liver tissue of fathead minnow (Pimephales promelas). Using GSEA, we tested the hypothesis that fathead livers, in response to methylmercury exposure, would exhibit gene expression patterns similar to diseased human livers.

Results

We describe an enhanced annotation of the fathead minnow microarray platform with human gene symbols. This resource is now compatible with the GSEA approach for gene-class testing. We confirmed that GSEA, using this enhanced microarray platform, is able to recover results consistent with a previous analysis of fathead minnow exposure to methylmercury using standard analytical approaches. Using GSEA to compare fathead gene expression profiles to human phenotypes, we also found that fathead methylmercury-treated livers exhibited expression profiles that are homologous to human systems & pathways and results in damage that is similar to those of human liver damage associated with hepatocellular carcinoma and hepatitis B.

Conclusions

This study describes a powerful resource for enabling the use of non-mammalian model organisms in the study of human health significance. Results of microarray gene expression studies involving fathead minnow, typically used for aquatic ecological toxicology studies, can now be used to generate hypotheses regarding consequences of contaminants and other stressors on humans. The same approach can be used with other model organisms with microarray platforms annotated in a similar manner.

Significance of expression of vascular endothelial growth factor B and its splice isoforms in different types of liver lesions

AIM: To detect the mRNA expression of vascular endothelial cell growth factor B (VEGF-B) and its splice isoforms VEGF-B167 and VEGF-B186 in different types of liver lesions and to assess their clinical significance.

METHODS: The mRNA expression of VEGF-B, VEGF-B167 and VEGF-B186 in liver cancer, cancer-adjacent tissue, liver cirrhosis, chronic hepatitis B, and normal liver tissue was detected by quantitative real-time reverse transcription-polymerase chain reaction (RT-PCR). The correlation of VEGF-B, VEGF-B167, and VEGF-B186 expression with the clinical pathological data of patients was analyzed, and survival analysis was performed using follow-up data.

RESULTS: There were no statistical differences in the expression levels of total VEGF-B and VEGF-B186 among each group, while the expression level of VEGF-B167 mRNA was significantly different among each group, highest in the normal group but lowest in liver cirrhosis group (252.59 vs 168.00, P = 0.005). The expression level of VEGF-B167 mRNA was significantly higher in the liver cancer group than in the chronic hepatitis B group (234.13 vs 170.72, 168.00, both P < 0.05). The overall survival rate and tumor-free survival rate of patients with low VEGF-B167 expression tended to be higher than those of patients with high VEGF-B167 expression (P = 0.097, 0.023). The expression levels of total VEGF-B, VEGF-B167 and VEGF-B186 had no significant correlation with sex, age, virus infection, liver cirrhosis, Child-Pugh score, AFP score, tumor number or size, vascular invasion, TNM stage, or tumor differentiation.

CONCLUSION: VEGF-B is involved in hepatocarcinogenesis and VEGF-B167 plays a more important role than VEGF-B186 in this process. Patients with low VEGF-B167 expression have good prognosis since their postoperative overall survival rate and tumor-free survival rate are higher than those with high VEGF-B167 expression.