Universal hepatitis B vaccination: The only way to eliminate hepatocellular carcinoma?

Engineering cancer cell membranes with endogenously upregulated HSP70 as a reinforced antigenic repertoire for the construction of material-free prophylactic cancer vaccines

Immune cells distinguish cancer cells mainly relying on their membrane-membrane communication. The major challenge of cancer vaccines exists in difficult identification of cancer neoantigens and poor understanding over immune recognition mechanisms against cancer cells, particularly the combination among multiple antigens and the cooperation between antigens and immune-associated proteins. We exploit cancer cell membranes as the whole cancer antigen repertoire and reinforce its immunogenicity by cellular engineering to modulate the cytomembrane's immune-associated functions. This study reports a vaccine platform based on radiation-engineered cancer cells, of which the membrane HSP70 protein as the immune chaperon/traitor is endogenously upregulated. The resulting positive influences are shown to cover immunogenic steps occurring in antigen-presenting cells, including the uptake and the cross-presentation of the cancer antigens, thus amplifying cancer-specific immunogenicity. Membrane vaccines offer chances to introduce desired metal ions through membrane-metal complexation. Using Mn2+ ion as the costimulatory interferon genes agonist, immune activity is enhanced to further boost adaptive cancer immunogenicity. Results have evidenced that this artificially engineered membrane vaccine with favorable bio-safety could considerably reduce tumorigenicity and inhibit tumor growth. This study provides a universally applicable and facilely available cancer vaccine platform by artificial engineering of cancer cells to inherit and amplify the natural merits of cancer cell membranes. STATEMENT OF SIGNIFICANCE: The major challenge of cancer vaccines exists in difficult identification of cancer neoantigens and poor understanding over immune recognition mechanisms against cancer cells, particularly the combination among multiple antigens and the cooperation between antigens and immune-associated proteins. Cancer cell membrane presents superior advantages as the whole cancer antigen repertoire, including the reported and the unidentified antigens, but its immunogenicity is far from satisfactory. Cellular engineering approaches offer chances to endogenously modulate the immune-associated functions of cell membranes. Such a reinforced vaccine based on the engineered cancer cell membranes matches better the natural immune recognition pathway than the conventional vaccines.

Recent Advances in Protective Vaccines against Hepatitis Viruses: A Narrative Review

Vaccination has been confirmed to be the safest and, sometimes, the only tool of defense against threats from infectious diseases. The successful history of vaccination is evident in the control of serious viral infections, such as smallpox and polio. Viruses that infect human livers are known as hepatitis viruses and are classified into five major types from A to E, alphabetically. Although infection with hepatitis A virus (HAV) is known to be self-resolving after rest and symptomatic treatment, there were 7134 deaths from HAV worldwide in 2016. In 2019, hepatitis B virus (HBV) and hepatitis C virus (HCV) resulted in an estimated 820,000 and 290,000 deaths, respectively. Hepatitis delta virus (HDV) is a satellite virus that depends on HBV for producing its infectious particles in order to spread. The combination of HDV and HBV infection is considered the most severe form of chronic viral hepatitis. Hepatitis E virus (HEV) is another orally transmitted virus, common in low- and middle-income countries. In 2015, it caused 44,000 deaths worldwide. Safe and effective vaccines are already available to prevent hepatitis A and B. Here, we review the recent advances in protective vaccines against the five major hepatitis viruses.

The Global Impact of Hepatitis B Vaccination on Hepatocellular Carcinoma

Over 1.5 million preventable new hepatitis B infections continue to occur each year and there are an estimated 296 million people living with chronic hepatitis B infection worldwide, resulting in more than 820,000 deaths annually due to liver cirrhosis and hepatocellular carcinoma (HCC). Hepatitis B vaccination remains the cornerstone of public health policy to prevent HCC and a vital component of the global hepatitis B elimination response. The WHO has set a 90% vaccination target to achieve hepatitis B elimination by 2030; however, there is wide variability in reported birth dose coverage, with global coverage at only 42%. In this review, we outline the global trends in hepatitis B vaccination coverage and the impact of hepatitis B vaccination on HCC incidence and discuss the challenges and enabling factors for achieving WHO 2030 hepatitis B vaccination coverage targets.

A comprehensive evaluation of single nucleotide polymorphisms associated with hepatocellular carcinoma risk in Asian populations: A systematic review and network meta-analysis

BACKGROUND

Single nucleotide polymorphisms (SNPs) have been inconsistently associated with hepatocellular carcinoma (HCC) risk. This meta-analysis aimed to synthesize relevant data on SNPs associated with HCC in the Asian population.

METHODS

Databases were searched to identify association studies of SNPs and HCC in Asians published through January 2019. Summary odds ratios (ORs) and 95% confidence intervals (CIs) were calculated based on 41 studies (13,167 patients with HCC and 15,886 noncancer controls). Network meta-analysis and Thakkinstian's algorithm were used to select the most appropriate genetic model, along with false positive report probability (FPRP) for noteworthy associations.

RESULTS

Eleven SNPs meeting the inclusion criteria were tested for association with HCC, including CCND1 rs9344, PTGS2 rs689466, IL18 rs187238 and rs1946518, KIF1B rs17401966, MDM2 rs2279744, MIR146A rs2910164, MIR149 rs2292832, MIR196A2 rs11614913, MIR499A rs3746444, and TGFB1 rs1800469. A significant increase for HCC risk was observed for MDM2 rs2279744, and the dominant (pooled OR = 1.59, 95% CI: 1.26-2.00) and codominant (pooled OR = 1.37, 95% CI: 1.18-1.60) models were determined to be the most appropriate models. MIR499A rs3746444 also showed a significant association with HCC risk under the allele contrast model (pooled OR = 1.36, 95% CI: 1.05-1.77). Only the significance of MDM2 rs2279744 was noteworthy (FPRP < 0.2).

CONCLUSIONS

MDM2 rs2279744 is associated with HCC susceptibility in Asians, and the dominant and codominant models are likely the most appropriate models to estimate HCC risk.

Using a chronic hepatitis B Registry to support population-level liver cancer prevention in Sydney, Australia

Background

Approximately 1% of Australians have chronic hepatitis B (CHB), which disproportionately affects people born in hepatitis B-endemic countries. Currently, approximately half of the people affected remain undiagnosed and antiviral treatment uptake is suboptimal (~5%). This increases the likelihood of developing end-stage disease complications, particularly hepatocellular cancer (HCC), and largely accounts for the significant increases in HCC incidence and mortality in Australia over the last decades. As our previous economic modeling suggested that CHB screening and treatment is cost-effective, we tested the feasibility of a primary care-based model of CHB diagnosis and management to prevent HCC.

Materials and methods

From 2009 to 2016, the B Positive program trialed a CHB screening and management program in an area of high disease prevalence in Sydney, Australia. Trained local primary care providers (general practitioners) screened and managed their CHB patients using a purpose-built CHB Registry and a risk stratification algorithm, which allocated patients to ongoing primary care-based management or specialist referral.

Results

The program enrolled and followed up >1,500 people (25% of the target population). Their median age was 48 years, with most participants being born in China (50%) or Vietnam (32%). The risk stratification algorithm allocated most Registry participants (n=847 or 79%) to primary care-based management, reducing unnecessary specialist referrals. The level of antiviral treatment uptake in Registry patients was 18%, which was the optimal level in this population group.

Conclusion

This pilot program demonstrated that primary care-based hepatitis B diagnosis and management is acceptable to patients and their care providers and significantly increases compliance with treatment guidelines. This would suggest that scaling up access to hepatitis B treatment is achievable and can provide a means to operationalize a population-level approach to CHB management and liver cancer prevention.