Impact of hepatitis B virus (HBV) X gene integration in liver tissue on hepatocellular carcinoma development in serologically HBV-negative chronic hepatitis C patients

Effect of previous infection with hepatitis B virus on the incidence of hepatocellular carcinoma after sustained virologic response in patients with chronic hepatitis C virus infection

Previous infection with hepatitis B virus (HBV), which is assessed by HBV core antibody (HBcAb) or surface antibody (HBsAb) titres, has reportedly been associated with an increased risk of developing hepatocellular carcinoma (HCC). We investigated the influence of previous HBV infection on the incidence of HCC in patients with hepatitis C virus (HCV) infection who achieved eradication of HCV, that is sustained virologic response (SVR). Both HBcAb and HBsAb were measured in a total of 1214 patients with HCV infection who had not been coinfected with HBV, as determined by both negative HBs antigen and HBV DNA, and in whom SVR was confirmed. Patients were followed up for a median of 5.7 years, and the incidence of post-SVR HCC was compared based on HBcAb and/or HBsAb. In both univariate and multivariate analyses, the incidence of post-SVR HCC did not differ based on the presence of HBcAb or HBsAb. In conclusion, previous HBV infection has no impact on the incidence of HCC in patients with HCV after SVR.

Application of the Multi-Omics Liquid Biopsy Method M2P-HCC in Early Liver Cancer Screening for High-Risk Individuals with Hepatitis B-Related Liver Cancer

BACKGROUND

Hepatocellular carcinoma (HCC) is one of the most common malignant tumors worldwide, with low rates of early diagnosis and surgical resection. In recent years, with the rapid development of liquid biopsy technology, circulating tumor DNA (ctDNA) has emerged as a research hotspot in the field of precision medicine for liver cancer. Existing studies have demonstrated the suitability of ctDNA for combined detection with other liver cancer diagnostic markers, enabling a multi-index analysis. In recent years, a novel prediction model has been developed for early liver cancer screening based on ctDNA liquid biopsy, M2P-HCC (methylation, mutation, and protein-HCC), mainly incorporating methylation changes, gene mutations, and protein markers associated with liver cancer. Preliminary validation in the HCCscreenTM Investigational (HIT, ChiCTR1800020233) study, which focused on screening early liver cancer in communities with Hepatitis B surface antigen (HBsAg) positivity, yielded promising results with 100% sensitivity and 94% specificity. However, it remains uncertain whether M2P-HCC can be effectively applied in high-risk populations for Hepatitis B-associated liver cancer, warranting further research.

METHODS

Patients who were under long-term follow-up at the outpatient clinic of the Infectious Diseases Center of West China Hospital of Sichuan University from December 2020 to January 2023 were recruited in this prospective observational study and underwent the M2P-HCC test. The study population consisted of high-risk patients with Hepatitis B-related liver cancer who met the inclusion criteria. Patients with a history of previous malignancy, recent blood transfusion, autoimmune diseases, and human immunodeficiency virus (HIV) infection were excluded. Clinical data were collected at a baseline, and all patients underwent the M2P-HCC blood test. Based on the test results, they were categorized into positive, early-warning, and negative groups. Prospective cohort observation and regular follow-ups were performed for 6-8 months.

RESULTS

313 patients met the inclusion criteria and were included in the study. After 6-8 months of follow-up, HCC occurred in 41(13.1%) participants. The M2P-HCC test demonstrated good predictive performance with an area under the curve (AUC) of 0.88 (95% CI: 0.81-0.95, p < 0.001) and a cutoff value of 83 points (sensitivity 82.9% and specificity 85.7%). In contrast, the combination of alpha-fetoprotein (AFP) and ultrasound (US) yielded an inferior predictive performance (AUC 0.76 (95% CI: 0.69-0.84, p < 0.001), sensitivity 58.5%, and specificity 94.1%). Multivariate analyses revealed that M2P-HCC was an independent predictor of increased risk of HCC (OR = 1.16 [1.09-1.22], p < 0.001).

CONCLUSIONS

M2P-HCC liquid biopsy demonstrated good performance for early liver cancer screening in high-risk populations of Hepatitis B-related liver cancer, exhibiting better sensitivity than the combination of AFP and US.

New insights into hepatitis B virus lymphotropism: Implications for HBV-related lymphomagenesis

HBV is one of the most widespread hepatitis viruses worldwide, and a correlation between chronic infection and liver cancer has been clearly reported. The carcinogenic capacity of HBV has been reported for other solid tumors, but the largest number of studies focus on its possible lymphomagenic role. To update the correlation between HBV infection and the occurrence of lymphatic or hematologic malignancies, the most recent evidence from epidemiological and in vitro studies has been reported. In the context of hematological malignancies, the strongest epidemiological correlations are with the emergence of lymphomas, in particular non-Hodgkin's lymphoma (NHL) (HR 2.10 [95% CI 1.34-3.31], p=0.001) and, more specifically, all NHL B subtypes (HR 2.14 [95% CI 1.61-2.07], p<0.001). Questionable and unconfirmed associations are reported between HBV and NHL T subtypes (HR 1.11 [95% CI 0.88-1.40], p=0.40) and leukemia. The presence of HBV DNA in peripheral blood mononuclear cells has been reported by numerous studies, and its integration in the exonic regions of some genes is considered a possible source of carcinogenesis. Some in vitro studies have shown the ability of HBV to infect, albeit not productively, both lymphomonocytes and bone marrow stem cells, whose differentiation is halted by the virus. As demonstrated in animal models, HBV infection of blood cells and the persistence of HBV DNA in peripheral lymphomonocytes and bone marrow stem cells suggests that these cellular compartments may act as HBV reservoirs, allowing replication to resume later in the immunocompromised patients (such as liver transplant recipients) or in subjects discontinuing effective antiviral therapy. The pathogenetic mechanisms at the basis of HBV carcinogenic potential are not known, and more in-depth studies are needed, considering that a clear correlation between chronic HBV infection and hematological malignancies could benefit both antiviral drugs and vaccines.

Hepadnaviral Lymphotropism and Its Relevance to HBV Persistence and Pathogenesis

Since the discovery of hepatitis B virus (HBV) over five decades ago, there have been many independent studies showing presence of HBV genomes in cells of the immune system. However, the nature of HBV lymphotropism and its significance with respect to HBV biology, persistence and the pathogenesis of liver and extrahepatic disorders remains underappreciated. This is in contrast to studies of other viral pathogens in which the capability to infect immune cells is an area of active investigation. Indeed, in some viral infections, lymphotropism may be essential, and even a primary mechanism of viral persistence, and a major contributor to disease pathogenesis. Nevertheless, there are advances in understanding of HBV lymphotropism in recent years due to cumulative evidence showing that: (i) lymphoid cells are a reservoir of replicating HBV, (ii) are a site of HBV-host DNA integration and (iii) virus genomic diversification leading to pathogenic variants, and (iv) they play a role in HBV resistance to antiviral therapy and (v) likely contribute to reactivation of hepatitis B. Further support for HBV lymphotropic nature is provided by studies in a model infection with the closely related woodchuck hepatitis virus (WHV) naturally infecting susceptible marmots. This animal model faithfully reproduces many aspects of HBV biology, including its replication scheme, tissue tropism, and induction of both symptomatic and silent infections, immunological processes accompanying infection, and progressing liver disease culminating in hepatocellular carcinoma. The most robust evidence came from the ability of WHV to establish persistent infection of the immune system that may not engage the liver when small quantities of virus are experimentally administered or naturally transmitted into virus-naïve animals. Although the concept of HBV lymphotropism is not new, it remains controversial and not accepted by conventional HBV researchers. This review summarizes research advances on HBV and hepadnaviral lymphotropism including the role of immune cells infection in viral persistence and the pathogenesis of HBV-induced liver and extrahepatic diseases. Finally, we discuss the role of immune cells in HBV diagnosis and assessment of antiviral therapy efficacy.

HBV-Integration Studies in the Clinic: Role in the Natural History of Infection

Hepatitis B virus (HBV) infection is a major global health problem causing acute and chronic liver disease that can lead to liver cirrhosis and hepatocellular carcinoma (HCC). HBV covalently closed circular DNA (cccDNA) is essential for viral replication and the establishment of a persistent infection. Integrated HBV DNA represents another stable form of viral DNA regularly observed in the livers of infected patients. HBV DNA integration into the host genome occurs early after HBV infection. It is a common occurrence during the HBV life cycle, and it has been detected in all the phases of chronic infection. HBV DNA integration has long been considered to be the main contributor to liver tumorigenesis. The recent development of highly sensitive detection methods and research models has led to the clarification of some molecular and pathogenic aspects of HBV integration. Though HBV integration does not lead to replication-competent transcripts, it can act as a stable source of viral RNA and proteins, which may contribute in determining HBV-specific T-cell exhaustion and favoring virus persistence. The relationship between HBV DNA integration and the immune response in the liver microenvironment might be closely related to the development and progression of HBV-related diseases. While many new antiviral agents aimed at cccDNA elimination or silencing have been developed, integrated HBV DNA remains a difficult therapeutic challenge.

Impact of AAV2 and Hepatitis B Virus Integration Into Genome on Development of Hepatocellular Carcinoma in Patients with Prior Hepatitis B Virus Infection

PURPOSE

Hepatitis B viral (HBV) DNA is frequently integrated into the genomes of hepatocellular carcinoma (HCC) in patients with chronic HBV infection (chronic HBV, hereafter), whereas the frequency of HBV integration in patients after the disappearance of HBV (prior HBV, hereafter) has yet to be determined. This study aimed to detect integration of HBV and adeno-associated virus type 2 (AAV2) into the human genome as a possible oncogenic event.

EXPERIMENTAL DESIGN

Virome capture sequencing was performed, using HCC and liver samples obtained from 243 patients, including 73 with prior HBV without hepatitis C viral (HCV) infection and 81 with chronic HBV.

RESULTS

Clonal HBV integration events were identified in 11 (15.0%) cases of prior HBV without HCV and 61 (75.3%) cases of chronic HBV (P < 0.001). Several driver genes were commonly targeted by HBV, leading to transcriptional activation of these genes; TERT [four (5.4%) vs. 15 (18.5%)], KMT2B [two (2.7%) vs. five (6.1%)], CCNE1 [zero vs. one (1.2%)], CCNA2 [zero vs. one (1.2%)]. Conversely, CCNE1 and CCNA2 were, respectively, targeted by AAV2 only in prior HBV. In liver samples, HBV genome recurrently integrated into fibrosis-related genes FN1, HS6ST3, KNG1, and ROCK1 in chronic HBV. There was not history of alcohol abuse and 3 patients with a history of nucleoside analogue treatment for HBV in 8 prior HBV with driver gene integration.

CONCLUSIONS

Despite the seroclearance of hepatitis B surface antigen, HBV or AAV2 integration in prior HBV was not rare; therefore, such patients are at risk of developing HCC.

Viral integration drives multifocal HCC during the occult HBV infection

BACKGROUND & AIMS

Although the prognosis of patients with occult hepatitis B virus (HBV) infection (OBI) is usually benign, a small portion may undergo cirrhosis and subsequently hepatocellular carcinoma (HCC). We studied the mechanism of life-long Integration of virus DNA into OBI host's genome, of which may induce hepatocyte transformation.

METHODS

We applied HBV capture sequencing on single cells from an OBI patient who, developed multiple HCC tumors and underwent liver resection in May 2013 at Tongji Hospital in China. Despite with the undetectable virus DNA in serum, we determined the pattern of viral integration in tumor cells and adjacent non-tumor cells and obtained the details of the viral arrangement in host genome, and furthermore the HBV integrated region in cancer genome.

RESULTS

HBV captured sequencing of tissues and individual cells revealed that samples from multiple tumors shared two viral integration sites that could affect three host genes, including CSMD2 on chr1 and MED30/EXT1 on chr8. Whole genome sequencing further indicated one hybrid chromosome formed by HBV integrations between chr1 and chr8 that was shared by multiple tumors. Additional 50 poorly differentiated liver tumors and the paired adjacent non-tumors were evaluated and functional studies suggested up-regulated EXT1 expression promoted HCC growth. We further observed that the most somatic mutations within the tumor cell genome were common among the multiple tumors, suggesting that HBV associated, multifocal HCC is monoclonal in origin.

CONCLUSION

Through analyzing the HBV integration sites in multifocal HCC, our data suggested that the tumor cells were monoclonal in origin and formed in the absence of active viral replication, whereas the affected host genes may subsequently contribute to carcinogenesis.

Integration of hepatitis B virus S gene impacts on hepatitis B surface antigen levels in patients with antiviral therapy

BACKGROUND AND AIM

The aim of this study is to investigate the impact of hepatitis B virus (HBV) S gene integration on serum hepatitis B surface antigen (HBsAg) levels in chronic hepatitis B with long-term nucleos(t)ide analogue (NUC) therapy.

METHODS

Chronic hepatitis B patients who performed liver biopsy at baseline and treated with long-term NUC therapy were recruited. The integration of HBV S gene in baseline liver biopsy specimen was detected by Alu polymerase chain reaction method. Serum HBsAg levels were measured at baseline and the second year and the fourth year after NUC therapy by Roche reagent, respectively. Serum HBsAg levels between HBV S gene integrated group and nonintegrated group were compared and analyzed.

RESULTS

Seventy patients were eligible for this study. Among them, 11 (15.7%) were found to have HBV S gene integration in their baseline liver biopsy specimens. Similar significant decrease of HBsAg levels was found in both integrated and nonintegrated groups (2.63 vs 2.65 log IU/mL, P = 0.478) after the first 2 years of NUC therapy. Thereafter, the decrease of HBsAg level from 2 to 4 years after therapy was largely unchanged in integrated group as compared with that of nonintegrated group (0.1 vs 2.53 log IU/mL, P = 0.002), with statistical difference.

CONCLUSIONS

Serum HBsAg could be originated from the expression of the integrated HBV S gene in patients with S gene integration, which implicated the limitations when regarding HBsAg as a surrogate biomarker of covalently closed circular DNA activity and as an indicator of safe NUC discontinuation.

Hepatitis B and Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) is one of the leading causes of cancer death worldwide, and its incidence has been increasing in the last decade largely in parallel to the incidence and duration of exposure to hepatitis B and C. The widespread implementation of hepatitis B vaccine, hepatitis B antivirals, and the introduction of direct antiviral therapies for hepatitis C virus may have a substantial impact in reducing the incidence of HCC. This report reviews the risk factors and underlying mechanisms associated with the development of HCC in hepatitis B, along with advances in the diagnosis, imaging, and management of HCC.

MicroRNA expression in hepatocellular carcinoma after the eradication of chronic hepatitis virus C infection using interferon therapy

AIM

Hepatocellular carcinoma (HCC) develops in up to 5% of patients after the successful treatment of chronic hepatitis C virus (HCV) infection using interferon therapy. The aim of this study was to characterize miRNA expression in liver tissues from patients who achieved a sustained viral response (SVR).

METHODS

Seventy-one patients with resected HCC were enrolled into the present study: 61 HCC from patients with continuously infected HCV (HCV-HCC) and 10 from patients who had achieved SVR (SVR-HCC). We also included non-tumor tissues (SVR-NT) from four patients with SVR-HCC, and liver tissue (SVR-CH) from four SVR patients without HCC. Total RNA was extracted from liver samples. The miRNA expression patterns were analyzed using microarrays. In addition, target gene expression was quantified after miRNA overexpression in HEK293 cells.

RESULTS

We could discriminate between SVR-HCC and HCV-HCC with 75.36% accuracy using the expression pattern of six specific miRNA. The expression levels of 37 miRNA were significantly lower in HCV-HCC than in SVR-HCC, whereas the expression of 25 miRNA was significantly higher in HCV-HCC than SVR-HCC (P < 1.0E-05). The expression of thrombospondin 1 was regulated in an opposing manner by miR-30a-3p in SVR-HCC and HCV-HCC. In non-tumor tissues, the expression pattern of seven miRNA could distinguish between SVR-CH and SVR-NT with 87.50% accuracy.

CONCLUSION

Comprehensive miRNA expression analyses could not only differentiate between SVR-HCC and HCV-HCC but also forecast hepatocarcinogenesis after achieving SVR.

Significance of hepatitis virus infection in the oncogenic initiation of hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is one of the most common causes of cancer-related death worldwide. Chronic infection of hepatitis B virus (HBV) and/or hepatitis C virus (HCV) is a major risk factor in the development of the HCC, independently from excessive alcohol abuse and metabolic disease. Since the biology of HBV and HCV is different, their oncogenic effect may go through different mechanisms, direct and/or indirect. Viral hepatitis infection is associated with cellular inflammation, oxidative stress, and DNA damage, that may lead to subsequent hepatic injuries such as chronic hepatitis, fibrosis, cirrhosis, and finally HCC. Direct oncogenic properties of these viruses are related with their genotypic characteristics and the ability of viral proteins to interact with host proteins, thus altering the molecular pathways balance of the cells. In addition, the integration of HBV DNA, especially the gene S and X, in a particular site of the host genome can disrupt chromosomal stability and may activate various oncogenic mechanisms, including those in hematopoietic cells. Recently, several studies also had demonstrated that viral hepatitis could trigger the population of hepatic cancer stem cells. This review summarize available pre-clinical and clinical data in literature regarding oncogenic properties of HBV and HCV in the early initiation of HCC.

Asymptomatic Hepadnaviral Persistence and Its Consequences in the Woodchuck Model of Occult Hepatitis B Virus Infection

Woodchuck hepatitis virus (WHV) is molecularly and pathogenically closely related to hepatitis B virus (HBV). Both viruses display tropism towards hepatocytes and cells of the immune system and cause similar liver pathology, where acute hepatitis can progress to chronic hepatitis and to hepatocellular carcinoma (HCC). Two forms of occult hepadnaviral persistence were identified in the woodchuck-WHV model: secondary occult infection (SOI) and primary occult infection (POI). SOI occurs after resolution of a serologically apparent infection with hepatitis or after subclinical serologically evident virus exposure. POI is caused by small amounts of virus and progresses without serological infection markers, but the virus genome and its replication are detectable in the immune system and with time in the liver. SOI can be accompanied by minimal hepatitis, while the hallmark of POI is normal liver morphology. Nonetheless, HCC develops in about 20% of animals with SOI or POI within 3 to 5 years. The virus persists throughout the lifespan in both SOI and POI at serum levels rarely greater than 100 copies/mL, causes hepatitis and HCC when concentrated and administered to virus-naïve woodchucks. SOI is accompanied by virus-specific T and B cell immune responses, while only virus-specific T cells are detected in POI. SOI coincides with protection against reinfection, while POI does not and hepatitis develops after challenge with liver pathogenic doses >1000 virions. Both SOI and POI are associated with virus DNA integration into the liver and the immune system genomes. Overall, SOI and POI are two distinct forms of silent hepadnaviral persistence that share common characteristics. Here, we review findings from the woodchuck model and discuss the relevant observations made in human occult HBV infection (OBI).

Occult Hepatitis B (OBH) in Clinical Settings

CONTEXT

Occult hepatitis B (OHB), or persistent HBV DNA in patients who are hepatitis B surface antigen (HBsAg) negative, is a recently recognized entity. In an attempt to summarize the issues, this review presents an overview of the current proposed hypothesis on the clinical relevance and also updates the knowledge on the classification of OHB in different clinical settings.

EVIDENCE ACQUISITION

OHB COULD BE FOUND IN DIFFERENT POPULATION AND CLINICAL BACKGROUNDS INCLUDING: viral co-infections (with either human immunodeficiency or hepatitis C viruses), HBV chronic carriers, dialysis patients, transplantation settings and certain clinical situations (named in here: special clinical settings) with no apparent distinguishable clinical parameters.

RESULTS

The exact magnitude, pathogenesis, and clinical relevance of OHB are unclear. Even the possible role exerted by this cryptic infection on liver disease outcome, and hepatocellular carcinoma development remains unknown.

CONCLUSIONS

Monitoring of Individuals with positive anti-HBc, mass immunization programs and improvement in diagnostic tools seem to be important to control the probability of transmission of HBV through cryptic HBV infection.

Frequent detection of hepatitis B virus DNA in hepatocellular carcinoma of patients with sustained virologic response for hepatitis C virus

Hepatocellular carcinoma (HCC) develops several years after the eradication of hepatitis C virus (HCV) by interferon therapy. Risk factors for the development of HCC are only partly understood. To elucidate the role of occult hepatitis B virus (HBV) infection in hepatocarcinogenesis in patients with sustained virologic response, the prevalences of HBV-related makers were examined. Study group comprised 16 patients with sustained virologic response (group A) and 50 with HCV (group B). Anti-HBc and anti-HBs in serum were examined by enzyme-linked immunoassay. HBV DNA in liver was examined by nested polymerase chain reaction, using primers specific for genes encoding for HBx, HBsAg, HBcAg, and HBV cccDNA. Sequence of the amplified HBV DNA for 'a' determinant of HBsAg was determined in HCC. Anti-HBc was positive in 10 of 16 in group A and 25 of 50 in group B. HBV DNA in liver was detected in 12 of 16 in group A and 21 of 50 in group B (P = 0.044). In group A, HBV DNA in liver was detected frequently in patients without cirrhosis and in those with a longer period from the time of HCV eradication to the development of HCC. Mutation in 'a' determinant of HBsAg was found in three HCC of group A. Occult HBV infection may be one of the most important risk factors in hepatocarcinogenesis of Japanese patients with sustained virologic response.

Recent progress in genomic [corrected] research of liver cancer

Along the course of occurrence and development of liver cancer, the corresponding somatic cells accumulate some important genetic variations. These variations may be divided into two categories. For the genetic changes closely related to etiology of liver cancer, the well-known cases include insertion and integration of the hepatitis B virus (HBV) DNA after infection, and mutations at site 249 of the tumor suppressor gene p53 induced by exposure to aflatoxin B1. The secondary genetic changes include amplification and deletion of certain chromosome regions, mutations in p53 at the sites other than 249, as well as the mutational activation of the Wnt/beta-catenin signal pathway. The tumor cells with these genetic variations may gradually become the dominant clones under evolutionary selection. Besides, identification of genetic susceptible against risk of liver malignancy is also an important aspect of research in this field.