The oncogenic role of hepatitis delta virus in hepatocellular carcinoma

Characteristics and outcome of anti-hepatitis D virus positive patients with hepatocellular carcinoma

BACKGROUND & AIMS

Chronic hepatitis D virus (HDV) often leads to end-stage liver disease and hepatocellular carcinoma (HCC). Comprehensive data pertaining to large populations with HDV and HCC are missing, therefore we sought to assess the characteristics, management, and outcome of these patients, comparing them to patients with hepatitis B virus (HBV) infection.

METHODS

We analysed the Italian Liver Cancer database focusing on patients with positivity for HBV surface antigen and anti-HDV antibodies (HBV/HDV, n = 107) and patients with HBV infection alone (n = 588). Clinical and oncological characteristics, treatment, and survival were compared in the two groups.

RESULTS

Patients with HBV/HDV had worse liver function [Model for End-stage Liver Disease score: 11 vs. 9, p < .0001; Child-Turcotte-Pugh score: 7 vs. 5, p < .0001] than patients with HBV. HCC was more frequently diagnosed during surveillance (72.9% vs. 52.4%, p = .0002), and the oncological stage was more frequently Milan-in (67.3% vs. 52.7%, p = .005) in patients with HBV/HDV. Liver transplantation was more frequently performed in HBV/HDV than in HBV patients (36.4% vs. 9.5%), while the opposite was observed for resection (8.4% vs. 20.1%, p < .0001), and in a competing risk analysis, HBV/HDV patients had a higher probability of receiving transplantation, independently of liver function and oncological stage. A trend towards longer survival was observed in patients with HBV/HDV (50.4 vs. 44.4 months, p = .106).

CONCLUSIONS

In patients with HBV/HDV, HCC is diagnosed more frequently during surveillance, resulting in a less advanced cancer stage in patients with more deranged liver function than HBV alone. Patients with HBV/HDV have a heightened benefit from liver transplantation, positively influencing survival.

Inflammatory Response in the Pathogenesis and Treatment of Hepatocellular Carcinoma: A Double-Edged Weapon

Hepatocellular carcinoma (HCC) is the most frequent among primary liver tumors (90%) and one of the main causes of cancer-related death. It develops usually in a chronically inflamed environment, ranging from compensatory parenchymal regeneration to fibrosis and cirrhosis: carcinogenesis can potentially happen in each of these stages. Inflammation determined by chronic viral infection (hepatitis B, hepatitis C, and hepatitis delta viruses) represents an important risk factor for HCC etiology through both viral direct damage and immune-related mechanisms. The deregulation of the physiological liver immunological network determined by viral infection can lead to carcinogenesis. The recent introduction of immunotherapy as the gold-standard first-line treatment for HCC highlights the role of the immune system and inflammation as a double-edged weapon in both HCC carcinogenesis and treatment. In this review we highlight how the inflammation is the key for the hepatocarcinogenesis in viral, alcohol and metabolic liver diseases.

Hepatocellular carcinoma and lipid metabolism: Novel targets and therapeutic strategies

Hepatocellular carcinoma (HCC) is an increasingly prevalent disease that is associated with high and continually rising mortality rates. Lipid metabolism holds a crucial role in the pathogenesis of HCC, in which abnormalities pertaining to the delicate balance of lipid synthesis, breakdown, and storage, predispose for the pathogenesis of the nonalcoholic fatty liver disease (NAFLD), a disease precursor to HCC. If caught early enough, HCC treatment may be curative. In later stages, treatment is only halting the inevitable outcome of death, boldly prompting for novel drug discovery to provide a fighting chance for this patient population. In this review, we begin by providing a summary of current local and systemic treatments against HCC. From such we discuss hepatic lipid metabolism and highlight novel targets that are ripe for anti-cancer drug discovery. Lastly, we provide a targeted summary of current known risk factors for HCC pathogenesis, providing key insights that will be essential for rationalizing future development of anti-HCC therapeutics.

HIV coinfection exacerbates HBV-induced liver fibrogenesis through a HIF-1α- and TGF-β1-dependent pathway

BACKGROUND & AIMS

Persons with chronic HBV infection coinfected with HIV experience accelerated progression of liver fibrosis compared to those with HBV monoinfection. We aimed to determine whether HIV and its proteins promote HBV-induced liver fibrosis in HIV/HBV-coinfected cell culture models through HIF-1α and TGF-β1 signaling.

METHODS

The HBV-positive supernatant, purified HBV viral particles, HIV-positive supernatant, or HIV viral particles were directly incubated with cell lines or primary hepatocytes, hepatic stellate cells, and macrophages in mono or 3D spheroid coculture models. Cells were incubated with recombinant cytokines and HIV proteins including gp120. HBV sub-genomic constructs were transfected into NTCP-HepG2 cells. We also evaluated the effects of inhibitor of HIF-1α and HIV gp120 in a HBV carrier mouse model that was generated via hydrodynamic injection of the pAAV/HBV1.2 plasmid into the tail vein of wild-type C57BL/6 mice.

RESULTS

We found that HIV and HIV gp120, through engagement with CCR5 and CXCR4 coreceptors, activate AKT and ERK signaling and subsequently upregulate hypoxia-inducible factor-1α (HIF-1α) to increase HBV-induced transforming growth factor-β1 (TGF-β1) and profibrogenic gene expression in hepatocytes and hepatic stellate cells. HIV gp120 exacerbates HBV X protein-mediated HIF-1α expression and liver fibrogenesis, which can be alleviated by inhibiting HIF-1α. Conversely, TGF-β1 upregulates HIF-1α expression and HBV-induced liver fibrogenesis through the SMAD signaling pathway. HIF-1α small-interfering RNA transfection or the HIF-1α inhibitor (acriflavine) blocked HIV-, HBV-, and TGF-β1-induced fibrogenesis.

CONCLUSIONS

Our findings suggest that HIV coinfection exacerbates HBV-induced liver fibrogenesis through enhancement of the positive feedback between HIF-1α and TGF-β1 via CCR5/CXCR4. HIF-1α represents a novel target for antifibrotic therapeutic development in HBV/HIV coinfection.

IMPACT AND IMPLICATIONS

HIV coinfection accelerates the progression of liver fibrosis compared to HBV monoinfection, even among patients with successful suppression of viral load, and there is no sufficient treatment for this disease process. In this study, we found that HIV viral particles and specifically HIV gp120 promote HBV-induced hepatic fibrogenesis via enhancement of the positive feedback between HIF-1α and TGF-β1, which can be ameliorated by inhibition of HIF-1α. These findings suggest that targeting the HIF-1α pathway can reduce liver fibrogenesis in patients with HIV and HBV coinfection.

Exosomes as Conduits: Facilitating Hepatitis B Virus-Independent Hepatitis D Virus Transmission and Propagation in Hepatocytes

A number of research studies, including ours, have spotlighted exosomes as critical facilitators of viral dissemination. While hepatitis B virus (HBV) transmission through exosomes has been studied, the focus on its satellite virus, the hepatitis delta virus (HDV), has been unexplored in this context. HDV, although being a defective virus, can replicate its genome autonomously within hepatocytes, independently of HBV. Investigations on Huh7 cells revealed an intriguing phenomenon: the HDV proteins, S-HDAg and L-HDAg, are transmitted between cells without a complete viral structure. Detailed analysis further revealed that the expression of these proteins not only bolstered exosome secretion but also ensured their enrichment within these vesicles. Our experimental approach utilized transfection of various plasmids to examine the role of HDV RNA and proteins in the process. One salient finding was the differential propagation of the HDV proteins S-HDAg and L-HDAg, suggesting intricate molecular mechanisms behind their transmission. Notably, the purity of our exosome preparations was monitored using markers such as TSG101 and CD81. Importantly, these exosomes were found to carry both HDV RNA and proteins, highlighting their role in HDV dissemination. This novel study underscores the role of exosomes in mediating the transmission of HDV components between hepatocytes independent of HBV. These revelations about the exosomal pathway of HDV transmission provide a foundation for the development of innovative therapeutic strategies against HDV infections.

Hepatocellular Carcinoma: Prevention, Diagnosis, and Treatment

Hepatocellular carcinoma (HCC), the most prevalent form of liver cancer globally, poses a substantial health burden. Influenced by risk factors such as hepatitis B or C virus infections, chronic consumption of alcohol, and metabolic dysfunction, its exact etiology likely involves a complex interplay between viral infection, hepatocyte mutations, and chronic liver diseases like cirrhosis and metabolic dysfunction-associated steatohepatitis, and demographic variables like sex, race, and age. Disease stage significantly impacts the prognosis of HCC. There is significant potential for life-saving and socioeconomic benefits through the implementation of surveillance programs and the introduction of low-cost screening measures for high-risk groups; these screening measures include ultrasound imaging and blood tests. Treatment options for HCC encompass liver resection, transplantation, transarterial chemoembolization, radiation therapy, chemotherapy, targeted therapy, and immunotherapy. Despite therapeutic advances, treating advanced HCC remains challenging, emphasizing the need for continued efforts in prevention, early detection, and development of treatments to improve prognosis and long-term survival.

Seroprevalence and molecular characterization of viral hepatitis and HIV co-infection in the Central African Republic

BACKGROUND

The Central African Republic (CAR) is one of the countries with the highest prevalence of viral hepatitis infection in the world. Coinfection with HIV increases the morbidity and mortality beyond that of mono-infection with either hepatitis or HIV. The present study describes the geographic distribution of viral hepatitis infections and molecular characterization of these viruses in the CAR.

METHODOLOGY

Out of 12,599 persons enrolled during the fourth Multiple Indicator Cluster Survey of 2010 in the CAR, 10,621 Dried Blood Spot (DBS) samples were obtained and stored at -20°C. Of these DBS, 4,317 samples were randomly selected to represent all regions of the CAR. Serological tests for hepatitis B, D, and C viruses were performed using the ELISA technique. Molecular characterization was performed to identify strains.

RESULTS

Of the 4,317 samples included, 53.2% were from men and 46.8% from women. The HBsAg prevalence among participants was 12.9% and that HBc-Ab was 19.7%. The overall prevalence of HCV was 0.6%. Co-infection of HIV/HBV was 1.1% and that of HBV/HDV was 16.6%. A total of 77 HBV, 6 HIV, and 6 HDV strains were successfully sequenced, with 72 HBV (93.5%) strains belonging to genotype E and 5 (6.5%) strains belonging to genotype D. The 6 HDV strains all belonged to clade 1, while 4 recombinants subtype were identified among the 6 strains of HIV.

CONCLUSION

Our study found a high prevalence of HBV, HBV/HDV and HBV/HIV co-infection, but a low prevalence of HCV. CAR remains an area of high HBV endemicity. This study's data and analyses would be useful for establishing an integrated viral hepatitis and HIV surveillance program in the CAR.

Association of hepatitis delta virus with liver morbidity and mortality: A systematic literature review and meta-analysis

BACKGROUND AND AIMS

Studies have suggested that patients with chronic hepatitis B, either co- or superinfected, have more aggressive liver disease progression than those with the HDV. This systematic literature review and meta-analysis examined whether HDV RNA status is associated with increased risk of advanced liver disease events in patients who are HBsAg and HDV antibody positive.

APPROACH AND RESULTS

A total of 12 publications were included. Relative rates of progression to advanced liver disease event for HDV RNA+/detectable versus HDV RNA-/undetectable were extracted for analysis. Reported OR and HRs with 95% CI were pooled using the Hartung-Knapp-Sidik-Jonkman method for random-effects models. The presence of HDV RNA+ was associated with an increased risk of any advanced liver disease event [random effect (95% CI): risk ratio: 1.48 (0.93, 2.33); HR: 2.62 (1.55, 4.44)]. When compared to the patients with HDV RNA- status, HDV RNA+ was associated with a significantly higher risk of progressing to compensated cirrhosis [risk ratio: 1.74 (1.24, 2.45)] decompensated cirrhosis [HR: 3.82 (1.60, 9.10)], HCC [HR: 2.97 (1.87, 4.70)], liver transplantation [HR: 7.07 (1.61, 30.99)], and liver-related mortality [HR: 3.78 (2.18, 6.56)].

CONCLUSIONS

The patients with HDV RNA+ status have a significantly greater risk of liver disease progression than the patients who are HDV RNA-. These findings highlight the need for improved HDV screening and linkage to treatment to reduce the risk of liver-related morbidity and mortality.

Hepatitis Delta Virus and Hepatocellular Carcinoma

The hepatitis D virus (HDV) is a compact, enveloped, circular RNA virus that relies on hepatitis B virus (HBV) envelope proteins to initiate a primary infection in hepatocytes, assemble, and secrete new virions. Globally, HDV infection affects an estimated 12 million to 72 million people, carrying a significantly elevated risk of developing cirrhosis, liver failure, and hepatocellular carcinoma (HCC) compared to an HBV mono-infection. Furthermore, HDV-associated HCC often manifests at a younger age and exhibits more aggressive characteristics. The intricate mechanisms driving the synergistic carcinogenicity of the HDV and HBV are not fully elucidated but are believed to involve chronic inflammation, immune dysregulation, and the direct oncogenic effects of the HDV. Indeed, recent data highlight that the molecular profile of HCC associated with HDV is unique and distinct from that of HBV-induced HCC. However, the question of whether the HDV is an oncogenic virus remains unanswered. In this review, we comprehensively examined several crucial aspects of the HDV, encompassing its epidemiology, molecular biology, immunology, and the associated risks of liver disease progression and HCC development.

The Role of Hepatitis Viruses as Drivers of Hepatocancerogenesis

Recently, metabolic associated steatotic liver disease (MASLD) became the leading cause of chronic liver disease worldwide and one of the most frequent causes of hepatocellular carcinoma (HCC). Nonetheless, in this epidemiological trend, viral hepatitis remains the major driver in hepatic carcinogenesis. Globally, hepatitis B virus (HBV) is the leading cause of hepatocellular carcinoma, with an overall attributable risk of approximately 40%, followed by hepatitis C virus (HCV), which accounts for 28-30% of cases, with significant geographic variations between the Eastern and Western world. Considering all the etiologies, HCC risk increases proportionally with the progression of liver disease, but the risk is consistently higher in patients with viral triggers. This evidence indicates that both direct (due to the oncogenic properties of the viruses) and indirect (through the mechanisms of chronic inflammation that lead to cirrhosis) mechanisms are involved, alongside the presence of co-factors contributing to liver damage (smoking, alcohol, and metabolic factors) that synergistically enhance the oncogenic process. The aim of this review is to analyze the oncogenic role of hepatitis viruses in the liver, evaluating epidemiological changes and direct and indirect viral mechanisms that lead to liver cancer.

Clinical long-term outcome of hepatitis D compared to hepatitis B monoinfection

BACKGROUND AND AIMS

Hepatitis D virus (HDV) infection causes the most severe form of chronic viral hepatitis. However, it is still unclear to what extent the underlying cirrhosis may contribute to disease progression. The aim of this study was to compare the long-term outcome of HDV infection with HBV monoinfection in a single-center cohort of both non-cirrhotic and cirrhotic patients.

METHOD

We retrospectively studied 175 patients with chronic hepatitis D (CHD) who were followed for at least 6 months (median of 6.3 (0.6-23.6) years). In addition, we selected 175 patients with HBV monoinfection (CHB) who were matched for gender, age, region of origin, HBeAg status, and bilirubin. Liver-related clinical end points were defined as hepatic decompensation (ascites, encephalopathy, variceal bleeding), liver transplantation, HCC, or liver-related death.

RESULTS

Clinical complications developed earlier (4.6 vs. 6.2 years) and more frequently (35.4% vs. 12.6%, p < 0.01) in CHD patients. In a multivariate Cox regression, HDV infection was independently associated with the development of end points (p < 0.01; HR: 3.0; 95% CI 1.4-6.4). However, in cirrhotic patients there were no significant differences between HBV and HDV in the development of end points. Besides, CHB patients with cirrhosis developed more frequently HCC (35.5%) than CHD patients with cirrhosis (18.5%).

CONCLUSION

Our results confirmed that HDV leads to a faster progression to cirrhosis compared to HBV. However, once cirrhosis is present, not HDV but the underlying cirrhosis is the dominate intrinsic risk factor for the development of liver-related end points and for the progression to HCC.

An Insight Into the Factors Affecting the Prevalence and Natural History of Hepatitis D

Epidemiological studies and recent metanalyses addressing hepatitis D have reported a wide variation in the prevalence of the disease. Between 4.5% to 15% of all hepatitis B surface antigen (HBsAg) positive patients are thought to harbor the hepatitis D virus. The emergent variation in prevalence can be attributed to several factors. Unsurprisingly, published literature shows that the prevalence of the disease is higher in areas where aggregate viral hepatitis infections are endemic and amongst groups with high-risk practices facilitating the horizontal transfer. Meanwhile, the natural history of the disease is influenced by the genotype of the virus, the hepatitis D virus (HDV) RNA levels, HBV-HDV codominance, HBsAg titers, HBV genotype, nutritional status, HIV co-infection, and prior treatment. Together these factors contribute to the accelerated development of fibrosis and the increased risk of hepatocellular carcinoma. Superinfection with genotype 1 results in rapid progression to cirrhosis with lower rates of remission. Genotype 3 follows an aggressive course but shows a good response to interferon therapy. Other genotypes have better outcomes. The course of the disease leading to these outcomes can be tracked by HDV-specific models integrating clinical surrogate markers and epidemiological factors such as age, region, alanine aminotransferase (ALT), gamma-glutamyl transferase, albumin, platelets and cholinesterase, and liver stiffness.

Diagnosis and Management of Hepatitis Delta Virus Infection

Hepatitis D virus (HDV) depends on hepatitis B virus (HBV) to enter and exit hepatocytes and to replicate. Despite this dependency, HDV can cause severe liver disease. HDV accelerates liver fibrosis, increases the risk of hepatocellular carcinoma, and hastens hepatic decompensation compared to chronic HBV monoinfection. The Chronic Liver Disease Foundation (CLDF) formed an expert panel to publish updated guidelines on the testing, diagnosis, and management of hepatitis delta virus. The panel group performed network data review on the transmission, epidemiology, natural history, and disease sequelae of acute and chronic HDV infection. Based on current available evidence, we provide recommendations for screening, testing, diagnosis, and treatment of hepatitis D infection and review upcoming novel agents that may expand treatment options. The CLDF recommends universal HDV screening for all patients who are Hepatitis B surface antigen-positive. Initial screening should be with an assay to detect antibodies generated against HDV (anti-HDV). Patients who are positive for anti-HDV IgG antibodies should then undergo quantitative HDV RNA testing. We also provide an algorithm that describes CLDF recommendations on the screening, diagnosis, testing, and initial management of Hepatitis D infection.

Hepatitis Delta Infection: A Clinical Review

First discovered over 40 years ago, the hepatitis delta virus (HDV) is a unique RNA virus, requiring hepatitis B virus (HBV) antigens for its assembly, replication, and transmission. HBV and HDV can be acquired at the same time (coinfection) or HDV infection can occur in persons with chronic HBV (superinfection). Screening guidelines for HDV are inconsistent. While some guidelines recommend universal screening for all people with HBV, others recommend risk-based screening. Estimates of the global HDV prevalence range from 4.5 to 14.6% among persons with HBV; thus, there may be up to 72 million individuals with HDV worldwide. HDV is the most severe form of viral hepatitis. Compared to HBV monoinfection, HDV coinfection increases the risk of cirrhosis, hepatocellular carcinoma, hepatic decompensation, mortality, and necessity for liver transplant. Despite the severity of HDV, there are few treatment options. Pegylated interferon (off-label use) has long been the only available treatment, although bulevirtide is conditionally approved in some European countries. There are many potential treatments in development, but as yet, there are few effective and safe therapies for HDV infection. In conclusion, given the severity of HDV disease and the paucity of treatments, there is a great unmet need for HDV therapies.

Natural history of untreated HDV patients: Always a progressive disease?

A severe course has been described in early studies on chronic hepatitis D (CHD), with faster pace towards liver cirrhosis with subsequent high liver-related morbidity and mortality in the majority of patients. Earlier studies have included risk groups as people using intravenous drugs (PWID) or those with multiple co-morbidities. During the last decade, the epidemiological landscape of CHD has changed with domestic cases decreasing while increasing cases of CHD consisting of younger persons immigrating from endemic regions to low-endemic regions. Recently, further insights into the spectrum of the disease with an indolent disease course in a substantial proportion of persons with CHD have been gained. At diagnosis, ≥30%-50% had already established liver cirrhosis. Older age, liver cirrhosis, co-infection with HIV and lack of interferon (IFN) therapy are the main predictors of worse clinical outcome. The newly introduced and upcoming antivirals against CHD are highly anticipated, considering the historically low virological response rates to antiviral therapy. Further knowledge is needed to fully comprehend the natural course and the spectrum of this severe form of viral hepatitis. This is also to be able to evaluate the long-term effects of the new antivirals on disease progression.

The role of hepatitis B virus genome variations in HBV-related HCC: effects on host signaling pathways

Hepatocellular carcinoma (HCC) is a significant global health issue, with a high prevalence in many regions. There are variations in the etiology of HCC in different regions, but most cases are due to long-term infection with viral hepatitis. Hepatitis B virus (HBV) is responsible for more than 50% of virus-related HCC, which highlights the importance of HBV in pathogenesis of the disease. The development and progression of HBV-related HCC is a complex multistep process that can involve host, viral, and environmental factors. Several studies have suggested that some HBV genome mutations as well as HBV proteins can dysregulate cell signaling pathways involved in the development of HCC. Furthermore, it seems that the pathogenicity, progression of liver diseases, response to treatment and also viral replication are different among HBV mutants. Understanding the relationship between HBV genome variations and host signaling pathway alteration will improve our understanding of the molecular pathogenesis of HBV-related HCC. Furthermore, investigating commonly dysregulated pathways in HBV-related HCC is necessary to discover more specific therapeutic targets and develop more effective strategies for HCC treatment. The objective of this review is to address the role of HBV in the HCC progression and primarily focus on the impacts of HBV genome variations on HCC-related signaling pathways.

Dictionary learning LASSO for feature selection with application to hepatocellular carcinoma grading using contrast enhanced magnetic resonance imaging

Introduction

The successful use of machine learning (ML) for medical diagnostic purposes has prompted myriad applications in cancer image analysis. Particularly for hepatocellular carcinoma (HCC) grading, there has been a surge of interest in ML-based selection of the discriminative features from high-dimensional magnetic resonance imaging (MRI) radiomics data. As one of the most commonly used ML-based selection methods, the least absolute shrinkage and selection operator (LASSO) has high discriminative power of the essential feature based on linear representation between input features and output labels. However, most LASSO methods directly explore the original training data rather than effectively exploiting the most informative features of radiomics data for HCC grading. To overcome this limitation, this study marks the first attempt to propose a feature selection method based on LASSO with dictionary learning, where a dictionary is learned from the training features, using the Fisher ratio to maximize the discriminative information in the feature.

Methods

This study proposes a LASSO method with dictionary learning to ensure the accuracy and discrimination of feature selection. Specifically, based on the Fisher ratio score, each radiomic feature is classified into two groups: the high-information and the low-information group. Then, a dictionary is learned through an optimal mapping matrix to enhance the high-information part and suppress the low discriminative information for the task of HCC grading. Finally, we select the most discrimination features according to the LASSO coefficients based on the learned dictionary.

Results and discussion

The experimental results based on two classifiers (KNN and SVM) showed that the proposed method yielded accuracy gains, compared favorably with another 5 state-of-the-practice feature selection methods.

Spontaneously Ruptured Hepatocellular Carcinoma: Computed Tomography-Based Assessment

Spontaneously ruptured hepatocellular carcinoma (SRHCC) is an uncommon and life-threatening complication in patients with hepatocellular carcinoma (HCC). It is usually associated with chronic liver disease and has a poor prognosis with a high mortality rate during the acute phase. SRHCC can cause a severe and urgent condition of acute abdomen disease and requires a correct diagnosis to achieve adequate treatment. Clinical presentation is related to the presence of hemoperitoneum, and abdominal pain is the most common symptom (66–100% of cases). Although the treatment approach is not unique, trans-arterial (chemo)embolization (TAE/TACE) followed by staged hepatectomy has shown better results in long-term survival. A multi-phase contrast-enhanced CT (CECT) scan is a pivotal technique in the diagnosis of SRHCC due to its diagnostic accuracy and optimal temporal resolution. The correct interpretation of the main CT findings in SRHCC, such as active contrast extravasation and the sentinel clot sign, is fundamental for a prompt and correct diagnosis. Furthermore, CT also plays a role as a post-operative control procedure, especially in patients treated with TAE/TACE. Therefore, a multi-phase CECT scan should be the diagnostic tool of choice in SRHCC since it suggests an immediate need for treatment with a consequent improvement in prognosis.

Hepatitis Virus and Hepatocellular Carcinoma: Recent Advances

Hepatocellular carcinoma (HCC) remains a global health challenge, causing 600,000 deaths each year. Infectious factors, including hepatitis B virus (HBV), hepatitis C virus (HCV) and hepatitis D virus (HDV), have long been considered the major risk factors for the development and progression of HCC. These pathogens induce hepatocyte transformation through a variety of mechanisms, including insertional mutations caused by viral gene integration, epigenetic changes, and the induction of long-term immune dysfunction. The discovery of these mechanisms, while advancing our understanding of the disease, also provides targets for new diagnostic and therapeutic approaches. In addition, the discovery and research of chronic HEV infection over the past decade indicate that this common hepatitis virus also seems to have the potential to induce HCC. In this review, we provide an overview of recent studies on the link between hepatitis virus and HCC, as well as new diagnostic and therapeutic approaches to HCC based on these findings. Finally, we also discuss the potential relationship between HEV and HCC. In conclusion, these associations will further optimize the diagnosis and treatment of infection-associated HCC and call for better management policies.

The immune landscape in hepatitis delta virus infection-Still an open field!

Hepatitis delta virus (HDV) is known to cause the most aggressive and severe form of viral hepatitis, yet it remained under-diagnosed but does require early diagnosis for accurate disease staging. Antibody to HDV (anti-HDV) is the primary screening tool and should be assessed in patients with hepatitis B surface antigen (HBsAg) positivity, as HDV is a satellite RNA virus of hepatitis B. Additionally, the viral load (HDV RNA) should be assessed in those with positive anti-HDV, to differentiate between active infection and resolved hepatitis delta. Data regarding immune responses in HDV are limited but show dysfunctional adaptive and innate immunity. Many studies however fail to distinguish between active and resolved infection. Limited treatments are available for HDV, but promise has been shown with the newly approved Bulevirtide, a first-in-class HBV entry inhibitor. Thus immune response during therapy requires further investigation, along with additional targets for HDV cure.

Attenuation of N-Nitrosodiethylamine -Induced Hepatocellular Carcinoma by Piceatannol and/or Cisplatin: The Interplay between Nuclear Factor (Erythroid Derived 2)-like 2 and Redox Status

BACKGROUND

The natural compound's alternative and complementary uses have increased hopes for hepatocellular cancer treatment (HCC).

OBJECTS

The goal of this study was to see if Piceatannol (PIC) in combination with cisplatin has a synergistic effect on N, N-nitrosodiethylamine (DEN)-induced HCC in rats.

METHODS

Tissue antioxidant enzymes, malondialdehyde (MDA), and nuclear factor erythroid 2 related factors 2 (Nrf2) and tumor necrosis factor α (TNF-α) gene expression were all measured. Nuclear Factor Kabba B (NF-κB) was also tested, as well as hepatic caspase 3 and NAD (P) H quinone oxidoreductase 1 (NQO1). Liver specimens were subjected to histopathological analysis.

RESULTS

When compared to the HCC group, piceatannol and/or cisplatin caused a significant improvement in liver function tests, as well as a significant modulation in Nrf2 gene expression and antioxidant enzyme activities, as well as a significant decrease in tissue MDA, TNF-α, NF-κB levels, NQO1 activity, and prompt and caspase-3 activities. When the PIC and/or cisplatin combination was compared to each of these compounds alone, the results were substantial.

CONCLUSION

PIC in combination with cisplatin has been shown to have a synergistic anticancer impact through modulating Nrf2 and redox state. In addition, adding PIC to an HCC therapy plan that includes chemotherapeutic medicines may boost the efficacy of cisplatin while reducing its negative effects.

Hepatocellular Carcinoma in Mongolia Delineates Unique Molecular Traits and a Mutational Signature Associated with Environmental Agents

PURPOSE

Mongolia has the world's highest incidence of hepatocellular carcinoma (HCC), with ∼100 cases/100,000 inhabitants, although the reasons for this have not been thoroughly delineated.

EXPERIMENTAL DESIGN

We performed a molecular characterization of Mongolian (n = 192) compared with Western (n = 187) HCCs by RNA sequencing and whole-exome sequencing to unveil distinct genomic and transcriptomic features associated with environmental factors in this population.

RESULTS

Mongolian patients were younger, with higher female prevalence, and with predominantly HBV-HDV coinfection etiology. Mongolian HCCs presented significantly higher rates of protein-coding mutations (121 vs. 70 mutations per tumor in Western), and in specific driver HCC genes (i.e., APOB and TSC2). Four mutational signatures characterized Mongolian samples, one of which was novel (SBS Mongolia) and present in 25% of Mongolian HCC cases. This signature showed a distinct substitution profile with a high proportion of T>G substitutions and was significantly associated with a signature of exposure to the environmental agent dimethyl sulfate (71%), a 2A carcinogenic associated with coal combustion. Transcriptomic-based analysis delineated three molecular clusters, two not present in Western HCC; one with a highly inflamed profile and the other significantly associated with younger female patients.

CONCLUSIONS

Mongolian HCC has unique molecular traits with a high mutational burden and a novel mutational signature associated with genotoxic environmental factors present in this country.

Differential role of chronic liver diseases on the incidence of cancer: a longitudinal analysis among 248,224 outpatients in Germany

BACKGROUND

Chronic liver diseases, especially chronic hepatitis, are a known risk factor for the development of liver cancer. However, the risk of total cancer development and malignant potential from these diseases is largely unknown. Systematic data on the risk of cancer development from these diseases are missing. Therefore, the goal of this study is to analyze the risk of total cancer development in chronic liver diseases.

METHODS

A cohort of 15,706 patients with chronic hepatitis and 15,706 patients without hepatitis were matched by propensity scoring from outpatient practices in Germany over a period of 15 years. Cox regression models were conducted to study the association between alcoholic hepatitis, autoimmune hepatitis, hepatitis B, hepatitis C and cancer incidence, including liver, other digestive organs, skin, prostate, breast and lymphoid and hematopoietic tissue cancer.

RESULTS

Within 10 years of the index date, 19.3% of patients with alcoholic hepatitis and 13.4% of non-hepatitis individuals were diagnosed with cancer (log-rank p = 0.035). These proportions were 15.0 vs. 9.9% (p = 0.078) for autoimmune hepatitis, 8.7 vs. 7.1% (p = 0.015) for hepatitis B, and 12.7 vs. 7.6% (p < 0.001) for hepatitis C. In regression analyses, only alcoholic hepatitis (HR: 1.84, 95% CI 1.32-2.54) and hepatitis C (HR: 2.10, 95% CI 1.77-2.50) were significantly associated with increased risk of cancer. There was a very strong positive association between hepatitis C and liver cancer (HR: 78.2 (95% CI 10.9-560.7). Furthermore, hepatitis C was associated with an increased risk of respiratory organ cancer (HR: 2.59, 95% CI 1.42-4.73).

CONCLUSION

This study confirms the strong association between chronic hepatitis and liver cancer, but also with an overall elevated cancer risk, and especially of cancer in the respiratory tract in patients with chronic hepatitis C.

Implementation of anti-HDV reflex testing among HBsAg-positive individuals increases testing for hepatitis D

Background & Aims

Although EASL guidelines recommend anti-HDV testing in all HBsAg-positive individuals, HDV infection remains an underdiagnosed condition. We describe the impact of an HDV screening program by reflex anti-HDV testing in all HBsAg-positive samples and compare the results before and after its implementation.

Methods

In total, 2,236 HBsAg-positive determinations were included from January 2018 to December 2021. Only the first sample from each participant was evaluated: 1,492 samples before reflex anti-HDV testing (2018–2020) and 744 samples after (2021). Demographic and clinical characteristics of anti-HDV-positive patients were collected.

Results

Before reflex testing, anti-HDV had been tested in 7.6% (114/1492) of HBsAg-positive individuals: 23% (91/390) attended in an academic hospital and only 2% (23/1,102) in primary care centres. After reflex testing was established, 93% (691/744) of HBsAg-positive cases were evaluated for anti-HDV: 91% (533/586) in the academic hospital and 100% (158/158) in primary care. The anti-HDV-positive prevalence was similar before and after reflex testing: 9.6% (11/114) and 8.1% (56/691), respectively. However, the absolute number of anti-HDV-positive patients increased. Most anti-HDV-positive patients were young, HBeAg-negative, Caucasian males. HDV-RNA was detectable in 35 (65%) of 54 tested, HBV-DNA was undetectable in 64%, and alanine aminotransferase levels were normal in 48%.

Conclusions

Anti-HDV reflex testing quintupled the absolute number of diagnoses of chronic hepatitis D infection. Before the reflex test, a large percentage of HBsAg-positive individuals had not undergone any anti-HDV determination. Implementation of reflex testing increases the diagnosis of patients with chronic hepatitis D.

Lay summary

Chronic hepatitis delta (CHD) is a viral disease caused by HDV, which requires the presence of HBV to propagate. HDV infection can cause rapid progression to cirrhosis, among other severe complications. The prevalence of CHD worldwide is controversial, and the infection often goes unrecognised, mainly because of unawareness among physicians. Use of reflex testing in other viral hepatitis has proven to increase detection and linking-to-care of infected patients. Implementation of anti-HDV testing in all HBsAg-positive patients has led to a 5-fold increase in the number of HDV diagnoses in an academic hospital and primary care centres.

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HDV testing rates in daily clinical practice are low despite EASL guidelines recommending universal screening.

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Implementation of HDV reflex testing led to a 5-fold increase in the number of HBV cases diagnosed with hepatitis D.

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Risk factors were unknown in 60% of anti-HDV positive cases, supporting systematic anti-HDV reflex testing in all HBsAg-positive patients.

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It would be of great value to assess the cost-effectiveness of anti-HDV reflex testing.

Viral hepatitis and hepatocellular carcinoma: From molecular pathways to the role of clinical surveillance and antiviral treatment

Hepatocellular carcinoma (HCC) is a global health challenge. Due to the high prevalence in low-income countries, hepatitis B virus (HBV) and hepatitis C virus infections remain the main risk factors for HCC occurrence, despite the increasing frequencies of non-viral etiologies. In addition, hepatitis D virus coinfection increases the oncogenic risk in patients with HBV infection. The molecular processes underlying HCC development are complex and various, either independent from liver disease etiology or etiology-related. The reciprocal interlinkage among non-viral and viral risk factors, the damaged cellular microenvironment, the dysregulation of the immune system and the alteration of gut-liver-axis are known to participate in liver cancer induction and progression. Oncogenic mechanisms and pathways change throughout the natural history of viral hepatitis with the worsening of liver fibrosis. The high risk of cancer incidence in chronic viral hepatitis infected patients compared to other liver disease etiologies makes it necessary to implement a proper surveillance, both through clinical-biochemical scores and periodic ultrasound assessment. This review aims to outline viral and microenvironmental factors contributing to HCC occurrence in patients with chronic viral hepatitis and to point out the importance of surveillance programs recommended by international guidelines to promote early diagnosis of HCC.

Emerging drugs for the treatment of hepatocellular carcinoma

INTRODUCTION

Hepatocellular carcinoma (HCC) remains a leading cause of liver related mortality. Cirrhosis of any etiology is the major risk factor although HCC can develop in its absence in patients with Hepatitis B and increasingly in those with non-alcoholic fatty liver disease. When detected at an early stage, curative options include surgical resection, liver transplantation and/or ablative therapies. Unfortunately, most cases of HCC are recognized at an advanced state when options are limited and non-curative. However new systemic therapies with tyrosine kinase inhibitors and immunotherapy have expanded therapeutic options in advanced HCC. Advances in systemic therapy have given patients with advanced HCC hope and prolonged their survival. Ongoing trials addressing different combination therapies with checkpoint inhibitors, tyrosine kinase inhibitors (TKI) or anti-VEGF therapies are expected to further enhance the management of advanced HCC.

AREAS COVERED

We discuss recent data and ongoing research efforsts to improve the treatment of hepatocellular carcinoma with discussion of current and upcoming systemic therapy combining agents of different classes.

EXPERT OPINION

Sustemic therapy for HCC is in evolution. The inclusion of immunotherapy to systemic therapy has revolutionalized the field of HCC treatment. Identificantion of the appropriate combination and sequence of systemic therapy coupled with discovery of reliable HCC biomarkers will lead to improved survival and inidividulized HCC therapy.

Innate and Adaptive Immunopathogeneses in Viral Hepatitis; Crucial Determinants of Hepatocellular Carcinoma

Viral hepatitis B (HBV) and hepatitis C (HCV) infections remain the most common risk factors for the development of hepatocellular carcinoma (HCC), and their heterogeneous distribution influences the global prevalence of this common type of liver cancer. Typical hepatitis infection elicits various immune responses within the liver microenvironment, and viral persistence induces chronic liver inflammation and carcinogenesis. HBV is directly mutagenic but can also cause low-grade liver inflammation characterized by episodes of intermittent high-grade liver inflammation, liver fibrosis, and cirrhosis, which can progress to decompensated liver disease and HCC. Equally, the absence of key innate and adaptive immune responses in chronic HCV infection dampens viral eradication and induces an exhausted and immunosuppressive liver niche that favors HCC development and progression. The objectives of this review are to (i) discuss the epidemiological pattern of HBV and HCV infections, (ii) understand the host immune response to acute and chronic viral hepatitis, and (iii) explore the link between this diseased immune environment and the development and progression of HCC in preclinical models and HCC patients.

Hepatitis B/D-Related Hepatocellular Carcinoma. A Clinical Literature Review

AIM

Given the current literature data, this article aims to shed light on the epidemiological and clinical effects of HBV, as well as its impact on the development of hepatocellular carcinoma (HCC).

METHODS

A review of the English language literature based on a MEDLINE (PubMed) database was searched. The keywords were cirrhosis, hepatocellular carcinoma, epidemiology, hepatitis delta virus, hepatitis B virus, and co-infection. All references from retrieved papers were reviewed systematically to find additional collection of reports.

RESULTS

The study has broadly confirmed the contribution of HDV viremia to liver disease and cirrhosis. However, uncertainty over the mechanism of action on HCC development remains. As the recent data has demonstrated, the HCC-HDV has a unique molecular profile which is distinct from that of HBV-HCC.

CONCLUSION

Owing to the dependence of HDV on HBV, it is not clear whether HCC is a consequence of the cumulative effect of both HBV and HDV, an effect of the underlying cirrhosis, or a direct oncogenic effect of HDV. Many questions concerning the oncogenic role of HDV remain unanswered. To better understand the role of HDV in carcinogenesis, studies at the molecular level that consider genotype differences should be increased. Multicenter, high-volume, and prospective studies that compare HBV/HDV co-infected and HBV-infected individuals will be pivotal in determining the oncogenic role of HDV.

Hepatocellular Carcinoma in 2021: An Exhaustive Update

Primary liver cancer is a challenging global health concern with an estimated more than a million persons to be affected annually by the year 2025. The commonest type is hepatocellular carcinoma (HCC), which has been increasing in incidence the world over, mostly due to chronic viral hepatitis B infection. In the last decade, paradigm changes in the etiology, understanding of molecular biology, and pathogenesis, including the role of gut microbiota; medical and surgical treatments, and outcome trends are notable. The application of omics-based technology has helped us unlock the molecular and immune landscape of HCC, through which novel targets for drug treatment such as immune-checkpoint inhibitors have been identified. Novel tools for the surveillance and diagnosis of HCC include protein-, genomics-, and composite algorithm-based clinical/biomarker panels. Magnetic resonance imaging-based novel techniques have improved HCC diagnosis through ancillary features that enhance classical criteria while positron emission tomography has shown value in prognostication. Identification of the role of gut microbiota in the causation and progression of HCC has opened areas for novel therapeutic research. A select group of patients still benefit from modified surgical and early interventional radiology treatments. Improvements in radiotherapy protocols, identification of parameters of futility among radiological interventions, and the emergence of novel first-line systemic therapies that include a combination of antiangiogenic and immune-checkpoint inhibitors have seen a paradigm change in progression-free and overall survival. The current review is aimed at providing exhaustive updates on the etiology, molecular biology, biomarker diagnosis, imaging, and recommended treatment options in patients with HCC.

Viral Hepatitis and Hepatocellular Carcinoma: State of the Art

Viral hepatitis is one of the main causes leading to hepatocellular carcinoma (HCC). The continued rise in incidence of HCC suggests additional factors following infection may be involved. This review examines recent studies investigating the molecular mechanisms of chronic hepatitis and its association with hepatocarcinogenesis. Hepatitis B virus patients with genotype C display an aggressive disease course leading to HCC more than other genotypes. Furthermore, hepatitis B excretory antigen (HBeAg) seems to be a more sensitive predictive tumor marker exhibiting a six-fold higher relative risk in patients with positive HBsAg and HBeAg than those with HBsAg only. Single or combined mutations of viral genome can predict HCC development in up to 80% of patients. Several mutations in HBx-gene are related with higher HCC incidence. Overexpression of the core protein in HCV leads to hepatocellular lipid accumulation associated with oncogenesis. Reduced number and decreased functionality of natural killer cells in chronic HCV individuals dysregulate their surveillance function in tumor and viral cells resulting in HCC. Furthermore, high T-cell immunoglobulin and mucin 3 levels supress CD8+ T-cells, which lead to immunological dysregulation. Hepatitis D promotes HCC development indirectly via modifications to innate immunity, epigenetic alterations and production of reactive oxygen species with the LHDAg being the most highly associated with HCC development. Summarizing the results, HBV and HCV infection represent the most associated forms of viral hepatitis causing HCC. Further studies are warranted to further improve the prediction of high-risk patients and development of targeted therapeutics preventing the transition from hepatic inflammation–fibrosis to cancer.

Hepatitis D virus (HDV): investigational therapeutic agents in clinical trials

INTRODUCTION

Chronic Hepatitis D virus (HDV) infection is a global disease leading to rapidly progressive liver disease with increased liver-related mortality and hepatocellular carcinoma. Therapies are minimally effective; however, an increased understanding of the HDV lifecycle has provided new potential drug targets. Thus, there is a growing number of investigational therapeutics under exploration for HDV with the potential for successful viral eradication.

AREAS COVERED

This review discusses the clinical impact of HDV infection and offers an in-depth look at the HDV life cycle. The authors examine current and new drug targets and the investigational therapies in clinical trials. The search strategy was based on PubMed database and clinicaltrials.gov which highlight the most up-to-date aspects of investigational therapies for chronic HDV infection.

The Prevalence and Serological Association of Hepatitis D Virus Genotypes in Taiwan

Hepatitis Delta Virus (HDV) is an RNA virus that requires the presence of hepatitis B surface antigen (HBsAg) to propagate into hepatocytes, with Genotype I being more prevalent globally. However, the prevalence of HDV genotypes in Taiwan is unknown. Accordingly, a cohort including 24 chronic HBV patients who received nucleos(t)ides (NUCs) between January 2002 and July 2018 was used to determine HDV genotypes and genotype specific serological association in chronic HBV carriers. HDV-positive genotypes in 18/24 (75%) males and 6/24 (25%) females were identified among chronic HBV patients. Viremia was lower in HDV-IV patients than in patients affected with other HDV genotypes (1.34 log₁₀ copies/mL vs. 3.30 log₁₀ copies/mL; p = 0.009). A logistics regression analysis revealed that HDV-IV was inversely proportional to HDV RNA (odds ratio [OR]/95% confidence intervals [CI]: 0.370/0.164-0.830; p = 0.017). The serologic association study indicated lower levels of creatinine (p = 0.047) and HDV-RNA (p = 0.009) in the HDV-IV group than the non-HDV-IV group but did not indicate any significant differences in the AST, ALT, bilirubin levels or other laboratory test factors. The three genotypes evident in Taiwan were HDV-I (4/24, 16.7%), HDV-II (6/24, 25.0%), and HDV-IV (14/24, 58.3%), and HDV-IV is the predominant HDV genotype in Taiwan. These results anticipate a clear understanding of HDV genotype serological association in chronic HBV carriers.

Unique Features of Hepatitis B Virus-Related Hepatocellular Carcinoma in Pathogenesis and Clinical Significance

Simple Summary

Hepatitis B virus (HBV) infection is the major risk factor for hepatocellular carcinoma (HCC). Understanding the unique features for HBV-induced HCC can shed new light on the unmet needs in its early diagnosis and effective therapy. During decades of chronic hepatitis B, hepatocytes undergoing repeated damage and regeneration accumulate genetic changes predisposing to HCC development. In addition to traditional mutations in viral and cellular oncogenes, HBV integration into the cell chromosomes is an alternative genetic change contributing to hepatocarcinogenesis. A striking male dominance in HBV-related HCC further highlights an interaction between androgen sex hormone and viral factors, which contributes to the gender difference via stimulating viral replication and activation of oncogenes preferentially in male patients. Meanwhile, a novel circulating tumor biomarker generated by HBV integration shows great potential for the early diagnosis of HCC. These unique HBV-induced hepatocarcinogenic mechanisms provide new insights for the future development of superior diagnosis and treatment strategies.

Abstract

Hepatitis B virus (HBV) infection is one of the important risk factors for hepatocellular carcinoma (HCC) worldwide, accounting for around 50% of cases. Chronic hepatitis B infection generates an inflammatory microenvironment, in which hepatocytes undergoing repeated cycles of damage and regeneration accumulate genetic mutations predisposing them to cancer. A striking male dominance in HBV-related HCC highlights the influence of sex hormones which interact with viral factors to influence carcinogenesis. HBV is also considered an oncogenic virus since its X and surface mutant proteins showed tumorigenic activity in mouse models. The other unique mechanism is the insertional mutagenesis by integration of HBV genome into hepatocyte chromosomes to activate oncogenes. HCC survival largely depends on tumor stages at diagnosis and effective treatment. However, early diagnosis by the conventional protein biomarkers achieves limited success. A new biomarker, the circulating virus–host chimera DNA from HBV integration sites in HCC, provides a liquid biopsy approach for monitoring the tumor load in the majority of HBV–HCC patients. To maximize the efficacy of new immunotherapies or molecular target therapies, it requires better classification of HCC based on the tumor microenvironment and specific carcinogenic pathways. An in-depth study may benefit both the diagnosis and treatment of HBV-related HCC.

Hepatitis D Virus and Hepatocellular Carcinoma

Hepatitis D virus (HDV) is a small, defective RNA virus that depends on hepatitis B virus (HBV) for virion assembly and transmission. It replicates within the nucleus of hepatocytes and interacts with several cellular proteins. Chronic hepatitis D is a severe and progressive disease, leading to cirrhosis in up to 80% of cases. A high proportion of patients die of liver decompensation or hepatocellular carcinoma (HCC), but the lack of large prospective studies has made it difficult to precisely define the rate of these long-term complications. In particular, the question of whether HDV is an oncogenic virus has been a matter of debate. Studies conducted over the past decade provided evidence that HDV is associated with a significantly higher risk of developing HCC compared to HBV monoinfection. However, the mechanisms whereby HDV promotes liver cancer remain elusive. Recent data have demonstrated that the molecular profile of HCC-HDV is unique and distinct from that of HBV-HCC, with an enrichment of upregulated genes involved in cell-cycle/DNA replication, and DNA damage and repair, which point to genome instability as an important mechanism of HDV hepatocarcinogenesis. These data suggest that HBV and HDV promote carcinogenesis by distinct molecular mechanisms despite the obligatory dependence of HDV on HBV.

Genomics of Viral Hepatitis-Associated Liver Tumors

Virus-related liver carcinogenesis is one of the main contributors of cancer-related death worldwide mainly due to the impact of chronic hepatitis B and C infections. Three mechanisms have been proposed to explain the oncogenic properties of hepatitis B virus (HBV) infection: induction of chronic inflammation and cirrhosis, expression of HBV oncogenic proteins, and insertional mutagenesis into the genome of infected hepatocytes. Hepatitis B insertional mutagenesis modifies the function of cancer driver genes and could promote chromosomal instability. In contrast, hepatitis C virus promotes hepatocellular carcinoma (HCC) occurrence mainly through cirrhosis development whereas the direct oncogenic role of the virus in human remains debated. Finally, adeno associated virus type 2 (AAV2), a defective DNA virus, has been associated with occurrence of HCC harboring insertional mutagenesis of the virus. Since these tumors developed in a non-cirrhotic context and in the absence of a known etiological factor, AAV2 appears to be the direct cause of tumor development in these patients via a mechanism of insertional mutagenesis altering similar oncogenes and tumor suppressor genes targeted by HBV. A better understanding of virus-related oncogenesis will be helpful to develop new preventive strategies and therapies directed against specific alterations observed in virus-related HCC.

The Dark Side of the Force: When the Immune System Is the Fuel of Tumor Onset

Nowadays, it is well accepted that inflammation is a critical player in cancer, being, in most cases, the main character of the process. Different types of tumor arise from sites of infection or chronic inflammation. This non-resolving inflammation is responsible for tumor development at different levels: it promotes tumor initiation, as well as tumor progression, stimulating both tumor growth and metastasis. Environmental factors, lifestyle and infections are the three main triggers of chronic immune activation that promote or increase the risk of many different cancers. In this review, we focus our attention on tumor onset; in particular, we summarize the knowledge about the cause and the mechanisms behind the inflammation-driven cancer development.

Hepatocellular carcinoma

Liver cancer remains a global health challenge, with an estimated incidence of >1 million cases by 2025. Hepatocellular carcinoma (HCC) is the most common form of liver cancer and accounts for ~90% of cases. Infection by hepatitis B virus and hepatitis C virus are the main risk factors for HCC development, although non-alcoholic steatohepatitis associated with metabolic syndrome or diabetes mellitus is becoming a more frequent risk factor in the West. Moreover, non-alcoholic steatohepatitis-associated HCC has a unique molecular pathogenesis. Approximately 25% of all HCCs present with potentially actionable mutations, which are yet to be translated into the clinical practice. Diagnosis based upon non-invasive criteria is currently challenged by the need for molecular information that requires tissue or liquid biopsies. The current major advancements have impacted the management of patients with advanced HCC. Six systemic therapies have been approved based on phase III trials (atezolizumab plus bevacizumab, sorafenib, lenvatinib, regorafenib, cabozantinib and ramucirumab) and three additional therapies have obtained accelerated FDA approval owing to evidence of efficacy. New trials are exploring combination therapies, including checkpoint inhibitors and tyrosine kinase inhibitors or anti-VEGF therapies, or even combinations of two immunotherapy regimens. The outcomes of these trials are expected to change the landscape of HCC management at all evolutionary stages.

The Changing Global Epidemiology of Hepatocellular Carcinoma

Hepatocellular carcinoma is among the leading causes of morbidity and mortality. Owing to the current epidemic of metabolic syndrome, the population affected by nonalcoholic fatty liver disease/nonalcoholic steatohepatitis continues to increase and now comprises a significant portion with those with hepatocellular carcinoma. The World Health Organization goal of obtaining universal hepatitis B virus vaccination has led to a global effort to improve vaccination, prevent mother-to-child transmission, and implement linkage to care to avoid the development of hepatocellular carcinoma. In contrast with the decreased burden of chronic hepatitis C virus, there has been an increase in new-onset acute hepatitis C virus.

Molecular mechanisms of viral hepatitis induced hepatocellular carcinoma

Chronic infection with viral hepatitis affects half a billion individuals worldwide and can lead to cirrhosis, cancer, and liver failure. Liver cancer is the third leading cause of cancer-associated mortality, of which hepatocellular carcinoma (HCC) represents 90% of all primary liver cancers. Solid tumors like HCC are complex and have heterogeneous tumor genomic profiles contributing to complexity in diagnosis and management. Chronic infection with hepatitis B virus (HBV), hepatitis delta virus (HDV), and hepatitis C virus (HCV) are the greatest etiological risk factors for HCC. Due to the significant role of chronic viral infection in HCC development, it is important to investigate direct (viral associated) and indirect (immune-associated) mechanisms involved in the pathogenesis of HCC. Common mechanisms used by HBV, HCV, and HDV that drive hepatocarcinogenesis include persistent liver inflammation with an impaired antiviral immune response, immune and viral protein-mediated oxidative stress, and deregulation of cellular signaling pathways by viral proteins. DNA integration to promote genome instability is a feature of HBV infection, and metabolic reprogramming leading to steatosis is driven by HCV infection. The current review aims to provide a brief overview of HBV, HCV and HDV molecular biology, and highlight specific viral-associated oncogenic mechanisms and common molecular pathways deregulated in HCC, and current as well as emerging treatments for HCC.

The genomic landscape of Mongolian hepatocellular carcinoma

Mongolia has the highest incidence of hepatocellular carcinoma (HCC) in the world, but its causative factors and underlying tumor biology remain unknown. Here, we describe molecular characteristics of HCC from 76 Mongolian patients by whole-exome and transcriptome sequencing. We present a comprehensive analysis of mutational signatures, driver genes, and molecular subtypes of Mongolian HCC compared to 373 HCC patients of different races and ethnicities and diverse etiologies. Mongolian HCC consists of prognostic molecular subtypes similar to those found in patients from other areas of Asia, Europe, and North America, as well as other unique subtypes, suggesting the presence of distinct etiologies linked to Mongolian patients. In addition to common driver mutations (TP53, CTNNB1) frequently found in pan-cancer analysis, Mongolian HCC exhibits unique drivers (most notably GTF2IRD2B, PNRC2, and SPTA1), the latter of which is associated with hepatitis D viral infection. These results suggest the existence of new molecular mechanisms at play in Mongolian hepatocarcinogenesis.