HLA Zygosity Increases Risk of Hepatitis B Virus-Associated Hepatocellular Carcinoma

HLA Genetic Diversity and Chronic Hepatitis B Virus Infection: Effect of Heterozygosity Advantage

This research aims to determine whether HLA heterozygosity confers a protective effect against hepatitis B virus infection by analyzing the relationship between HLA diversity and the risk of hepatitis B virus (HBV) infection. A total of 327 hepatitis B patients were selected and categorized based on their clinical status: 284 patients with chronic HBV infection and 43 patients with HBV-related liver cirrhosis (LC). The control group included 304 healthy individuals. HLA genotyping for 11 loci, including HLA class I and class II, was conducted using next-generation sequencing. The results of this study indicate a statistically significant negative correlation between HLA class II heterozygosity and the risk of HBV infection. Specifically, heterozygosity in HLA-DQB1 (OR = 0.49, 95% CI = 0.31-0.76, p = 0.01277) and HLA-DRB1 (OR = 0.42, 95% CI = 0.24-0.77, p = 0.01855) were significantly associated with protection. Subgroup analysis was conducted to explore the effect of HLA diversity among pathological subtypes (chronic hepatitis B and control group, liver cirrhosis and control group). For liver cirrhosis, compared with the control group, a decreased risk of LC was possibly associated with the heterozygosity of HLA class I locus B (OR = 0.24, 95% CI = 0.09-0.65, p = 0.0591), but this hypothesis was not confirmed by other studies. The diversity of HLA, measured by HLA heterozygosity, was associated with a protective effect against HBV infection.

Human Leukocyte Antigen-Allelic Variations May Influence the Age at Cancer Diagnosis in Lynch Syndrome

Lynch syndrome (LS) is an inherited cancer predisposition disorder associated with an elevated risk of developing various solid cancers, but mostly colorectal cancer (CRC). Despite having the same germline pathogenic variant (PV) in one of the mis-match repair genes or the EPCAM gene, Lynch syndrome variant heterozygotes (LSVH) exhibit a remarkable phenotypic variability in the risk of developing cancer. The role of human leukocyte antigen (HLA) in modifying cancer development risk prompted our hypothesis into whether HLA variations act as potential genetic modifiers influencing the age at cancer diagnosis in LSVH. To investigate this, we studied a unique cohort of 426 LSVH carrying the same germline PV in the hMLH1 gene (MLH1:c.1528C > T) in South Africa. We intuitively selected 100 LSVH with the greatest diversity in age at cancer diagnosis (N = 80) and the oldest cancer unaffected LSVH (N = 20) for a high-throughput HLA genotyping of 11 HLA class I and class II loci using the shotgun next-generation sequencing (NGS) technique on the Illumina MiSeq platform. Statistical analyses employed Kaplan-Meier survival analyses with log-rank tests, and Cox proportional hazards using binned HLA data to minimize type I error. Significant associations were observed between young age at cancer diagnosis and HLA-DPB1*04:02 (mean age: 37 y (25-50); hazard ratio (HR) = 3.37; corrected p-value (q) = 0.043) as well as HLA-DPB1 binned alleles (including HLA-DPB1*09:01, HLA-DPB1*10:01, HLA-DPB1*106:01, HLA-DPB1*18:01, HLA-DPB1*20:01, HLA-DPB1*26:01, HLA-DPB1*28:01, HLA-DPB1*296:01, and HLA-DPB1*55:01) (mean age: 37 y (17-63); HR = 2.30, q = 0.045). The involvement of HLA-DPB1 alleles in the age at cancer diagnosis may highlight the potential role of HLA class II in the immune response against cancer development in LSVH. When validated in a larger cohort, these high-risk HLA-DPB1 alleles could be factored into cancer risk prediction models for personalized cancer screening in LSVH.

Heterozygote advantage at HLA class I and II loci and reduced risk of colorectal cancer

Objective

Reduced diversity at Human Leukocyte Antigen (HLA) loci may adversely affect the host's ability to recognize tumor neoantigens and subsequently increase disease burden. We hypothesized that increased heterozygosity at HLA loci is associated with a reduced risk of developing colorectal cancer (CRC).

Methods

We imputed HLA class I and II four-digit alleles using genotype data from a population-based study of 5,406 cases and 4,635 controls from the Molecular Epidemiology of Colorectal Cancer Study (MECC). Heterozygosity at each HLA locus and the number of heterozygous genotypes at HLA class -I (A, B, and C) and HLA class -II loci (DQB1, DRB1, and DPB1) were quantified. Logistic regression analysis was used to estimate the risk of CRC associated with HLA heterozygosity. Individuals with homozygous genotypes for all loci served as the reference category, and the analyses were adjusted for sex, age, genotyping platform, and ancestry. Further, we investigated associations between HLA diversity and tumor-associated T cell repertoire features, as measured by tumor infiltrating lymphocytes (TILs; N=2,839) and immunosequencing (N=2,357).

Results

Individuals with all heterozygous genotypes at all three class I genes had a reduced odds of CRC (OR: 0.74; 95% CI: 0.56-0.97, p= 0.031). A similar association was observed for class II loci, with an OR of 0.75 (95% CI: 0.60-0.95, p= 0.016). For class-I and class-II combined, individuals with all heterozygous genotypes had significantly lower odds of developing CRC (OR: 0.66, 95% CI: 0.49-0.87, p= 0.004) than those with 0 or one heterozygous genotype. HLA class I and/or II diversity was associated with higher T cell receptor (TCR) abundance and lower TCR clonality, but results were not statistically significant.

Conclusion

Our findings support a heterozygote advantage for the HLA class-I and -II loci, indicating an important role for HLA genetic variability in the etiology of CRC.

Antigen presentation in cancer - mechanisms and clinical implications for immunotherapy

Over the past decade, the emergence of effective immunotherapies has revolutionized the clinical management of many types of cancers. However, long-term durable tumour control is only achieved in a fraction of patients who receive these therapies. Understanding the mechanisms underlying clinical response and resistance to treatment is therefore essential to expanding the level of clinical benefit obtained from immunotherapies. In this Review, we describe the molecular mechanisms of antigen processing and presentation in tumours and their clinical consequences. We examine how various aspects of the antigen-presentation machinery (APM) shape tumour immunity. In particular, we discuss genomic variants in HLA alleles and other APM components, highlighting their influence on the immunopeptidomes of both malignant cells and immune cells. Understanding the APM, how it is regulated and how it changes in tumour cells is crucial for determining which patients will respond to immunotherapy and why some patients develop resistance. We focus on recently discovered molecular and genomic alterations that drive the clinical outcomes of patients receiving immune-checkpoint inhibitors. An improved understanding of how these variables mediate tumour-immune interactions is expected to guide the more precise administration of immunotherapies and reveal potentially promising directions for the development of new immunotherapeutic approaches.

Association of HLA diversity with the risk of 25 cancers in the UK Biobank

BACKGROUND

The human leukocyte antigen (HLA) is a highly polymorphic region, and HLA diversity may play a role in presenting tumour-associated peptides and inducing immune responses. However, the effect of HLA diversity on cancers has not been fully assessed. We aimed to explore the role of HLA diversity on cancer development.

METHODS

A pan-cancer analysis was performed to evaluate the effect of HLA diversity, measured by HLA heterozygosity and HLA evolutionary divergence (HED), on the susceptibility of 25 cancers in the UK Biobank.

FINDINGS

We observed that the diversity of HLA class II locus was associated with a lower risk of lung cancer (OR_hetero = 0.94, 95% CI = 0.90-0.97, P = 1.29 × 10^-4) and head and neck cancer (OR_hetero = 0.91, 95% CI = 0.86-0.96, P = 1.56 × 10^-3). Besides, a lower risk of non-Hodgkin lymphoma was associated with an increased diversity of HLA class I (OR_hetero = 0.92, 95% CI = 0.87-0.98, P = 8.38 × 10^-3) and class II locus (OR_hetero = 0.89, 95% CI = 0.86-0.92, P = 1.65 × 10^-10). A lower risk of Hodgkin lymphoma was associated with the HLA class I diversity (OR_hetero = 0.85, 95% CI = 0.75-0.96, P = 0.011). The protective effect of HLA diversity was mainly observed in pathological subtypes with higher tumour mutation burden, such as lung squamous cell carcinoma (P = 9.39 × 10^-3) and diffuse large B cell lymphoma (P_{class I} = 4.12 × 10^-4; P_{class Ⅱ} = 4.71 × 10^-5), as well as the smoking subgroups of lung cancer (P = 7.45 × 10^-5) and head and neck cancer (P = 4.55 × 10^-3).

INTERPRETATION

We provided a systematic insight into the effect of HLA diversity on cancers, which might help to understand the etiological role of HLA on cancer development.

FUNDING

This study was supported by grants from the National Natural Science Foundation of China (82273705, 82003520); the Basic and Applied Basic Research Foundation of Guangdong Province, China (2021B1515420007); the Science and Technology Planning Project of Guangzhou, China (201804020094); Sino-Sweden Joint Research Programme (81861138006); the National Natural Science Foundation of China (81973131, 81903395, 81803319, 81802708).

HBV Infection-Related PDZK1 Plays an Oncogenic Role by Regulating the PI3K-Akt Pathway and Fatty Acid Metabolism and Enhances Immunosuppression

Background and Aim. Chronic hepatitis B virus (HBV) infection is the leading global cause of hepatocellular carcinoma (HCC). Few studies have been conducted concerning the HBV infection-related genes and their function. Methods. We compared differentially expressed genes (DGEs) in HBV-positive and -negative tumor samples and conducted a Spearman correlation study between the DGEs and HBV titers within The Cancer Genome Atlas (TCGA). Moreover, we validated the results of our in-house samples. Results. In this study, we discovered a series of genes that correlated statistically with HBV infection based on the TCGA database. These genes were related to increased inflammation and some oncogenic signaling pathways via Gene Set Enrichment Analysis (GSEA). PDZK1 is an ideal gene, which mostly relates positively to HBV infection; moreover, it is overexpressed in human HCC, especially in those HBV-infected HCCs. After analyzing the TCGA data and performing a verification study using our own samples, PDZK1 expression was investigated to be significantly associated with PI3K-Akt signaling and fatty acid metabolism. Further, single-sample GSEA analysis of tumor immune cell infiltration gene sets revealed that high PDZK1expression in HCC tissues was significantly associated with increased tumor-associated macrophages (TAMs) and regulatory T cells(Tregs). Conclusions. PDZK1 is an HBV infection-related gene, which plays oncogenic roles, possibly due to enhancing PI3K-Akt, fatty acid usage in tumor cells and TAMs, and Treg-induced immunosuppression.

Human leukocyte antigen class II gene diversity tunes antibody repertoires to common pathogens

Allelic diversity of human leukocyte antigen (HLA) class II genes may help maintain humoral immunity against infectious diseases. In this study, we investigated germline genetic variation in classical HLA class II genes and employed a systematic, unbiased approach to explore the relative contribution of this genetic variation in the antibody repertoire to various common pathogens. We leveraged a well-defined cohort of 800 adults representing the general Arab population in which genetic material is shared because of the high frequency of consanguineous unions. By applying a high-throughput method for large-scale antibody profiling to this well-defined cohort, we were able to dissect the overall effect of zygosity for classical HLA class II genes, as well as the effects associated with specific HLA class II alleles, haplotypes and genotypes, on the antimicrobial antibody repertoire breadth and antibody specificity with unprecedented resolution. Our population genetic studies revealed that zygosity of the classical HLA class II genes is a strong predictor of antibody responses to common human pathogens, suggesting that classical HLA class II gene heterozygosity confers a selective advantage. Moreover, we demonstrated that multiple HLA class II alleles can have additive effects on the antibody repertoire to common pathogens. We also identified associations of HLA-DRB1 genotypes with specific antigens. Our findings suggest that HLA class II gene polymorphisms confer specific humoral immunity against common pathogens, which may have contributed to the genetic diversity of HLA class II loci during hominine evolution.

Association Between Human Leukocyte Antigen Class I and II Diversity and Non-virus-associated Solid Tumors

Homozygosity at human leukocyte antigen (HLA) loci might lead to reduced immunosurveillance and increased disease risk, including cancers caused by infection or of hematopoietic origin. To investigate the association between HLA zygosity and risk of non-virus-associated solid tumors, we leveraged genome-wide association study (GWAS) data from over 28,000 individuals of European ancestry who participated in studies of 12 cancer sites (bladder, brain, breast, colon, endometrial, kidney, lung, ovary, pancreas, prostate, skin, and testis). Information on HLA zygosity was obtained by imputation; individuals were classified as homozygotes at a given locus when imputed to carry the same four-digit allele at that locus. We observed no evidence for an association between zygosity at six HLA loci and all cancers combined. Increase in number of homozygous at HLA class I loci, class II loci, or class I and II loci was also not associated with cancer overall (P trend = 0.28), with adjusted odds ratios (ORs) for risk-per-locus of 1.00 [95% confidence intervals (CIs) = 0.97, 1.03], 1.02 (0.99, 1.04), and 1.01 (0.99, 1.02), respectively. This study does not support a strong role for HLA zygosity on risk of non-virus-associated solid tumors.