Germline HLA landscape does not predict efficacy of pembrolizumab monotherapy across solid tumor types

Overview on biomarkers for immune oncology drugs

Although immune checkpoint inhibitors (ICIs) are widely used in clinical oncology, less than half of treated cancer patients derive benefit from this therapy. Both tumor- and host-related variables are implicated in response to ICIs. The predictive value of PD-L1 expression is confined only to several cancer types, so this molecule is not an agnostic biomarker. Highly elevated tumor mutation burden (TMB) caused either by excessive carcinogenic exposure or by a deficiency in DNA repair is a reliable indicator for ICI efficacy, as exemplified by tumors with high-level microsatellite instability (MSI-H). Other potentially relevant tumor-related characteristics include gene expression signatures, pattern of tumor infiltration by immune cells, and, perhaps, some immune-response modifying somatic mutations. Host-related factors have not yet been comprehensively considered in relevant clinical trials. Microbiome composition, markers of systemic inflammation [e.g., neutrophil-to-lymphocyte ratio (NLR)], and human leucocyte antigen (HLA) diversity may influence the efficacy of ICIs. Studies on ICI biomarkers are likely to reveal modifiable tumor or host characteristics, which can be utilized to direct the antitumor immune defense. Examples of the latter approach include tumor priming to immune therapy by cytotoxic drugs and elevation of ICI efficacy by microbiome modification.

The effect of human leukocyte antigen genotype on survival in advanced prostate cancer treated with primary androgen deprivation therapy: the KYUCOG-1401-A study

BACKGROUND

Immune editing, in which human leukocyte antigens (HLA) have critical roles, has been suggested to shape the landscape of human cancer. This study prospectively investigated whether HLA gene zygosity is associated with the prognosis of primary androgen deprivation therapy in advanced prostate cancer.

METHODS

KYUCOG-1401-A was conducted in conjunction with a prospective clinical trial (KYUCOG-1401). Among the patients enrolled in KYUCOG-1401 and treated with primary androgen deprivation therapy, only Japanese patients were included. HLA genotypes of HLA-A, B, C, DRB1, DQB1, and DPB1 were determined. The effect of divergence of HLA genotypes on time to progression, prostate cancer-specific survival, and overall survival was evaluated.

RESULTS

Among 127 patients, homozygosity for HLA-DRB1 (HR, 95% CI; 4.05, 1.54-10.7, P = 0.0047) and HLA-DQB1 (HR, 95% CI; 3.75, 1.47-9.58, P = 0.0058) was associated with an increased risk of prostate cancer-specific mortality. Patients with higher HLA evolutionary divergence scores at HLA-DQB1 (HR, 95% CI; 0.90, 0.82-0.97, P = 0.0093) had lower risks of prostate cancer-specific mortality. Androgen-responsive gene sets were upregulated in CD4low and CD8low tumors in the prostate cancer cohort, but not in the bladder and kidney cancer cohorts.

CONCLUSIONS

This study suggested that the diversity of HLA-II loci including HLA-DRB1 and HLA-DQB1 plays an important role in advanced prostate cancer survival, contributing to improved risk stratification in advanced prostate cancer. Moreover, it was shown that CD4+ T cells play an important role in androgen deprivation therapy, suggesting that immunotherapy targeting CD4+ T cells is promising for prostate cancer.

Advances in the understanding and therapeutic manipulation of cancer immune responsiveness: a Society for Immunotherapy of Cancer (SITC) review

Cancer immunotherapy-including immune checkpoint inhibition (ICI) and adoptive cell therapy (ACT)-has become a standard, potentially curative treatment for a subset of advanced solid and liquid tumors. However, most patients with cancer do not benefit from the rapidly evolving improvements in the understanding of principal mechanisms determining cancer immune responsiveness (CIR); including patient-specific genetically determined and acquired factors, as well as intrinsic cancer cell biology. Though CIR is multifactorial, fundamental concepts are emerging that should be considered for the design of novel therapeutic strategies and related clinical studies. Recent advancements as well as novel approaches to address the limitations of current treatments are discussed here, with a specific focus on ICI and ACT.

Loss of Heterozygosity (LOH) Affecting HLA Genes in Breast Cancer: Clinical Relevance and Therapeutic Opportunities

Major histocompatibility complex (MHC) class-I molecules (or Human Leucocyte Antigen class-I) play a key role in adaptive immunity against cancer. They present specific tumor neoantigens to cytotoxic T cells and provoke an antitumor cytotoxic response. The total or partial loss of HLA molecules can inhibit the immune system's ability to detect and destroy cancer cells. Loss of heterozygosity (LOH) is a common irreversible genetic alteration that occurs in the great majority of human tumors, including breast cancer. LOH at chromosome 6, which involves HLA genes (LOH-HLA), leads to the loss of an HLA haplotype and is linked to cancer progression and a weak response to cancer immunotherapy. Therefore, the loss of genes or an entire chromosomal region which are critical for antigen presentation is of particular importance in the search for novel prognostic and clinical biomarkers in breast cancer. Here, we review the role of LOH-HLA in breast cancer, its contribution to an understanding of cancer immune escape and tumor progression, and discuss how it can be targeted in cancer therapy.

HLA-A01 and HLA-B27 Supertypes, but Not HLA Homozygocity, Correlate with Clinical Outcome among Patients with Non-Small Cell Lung Cancer Treated with Pembrolizumab in Combination with Chemotherapy

INTRODUCTION

Maximal heterozygosity on the human leukocyte antigen (HLA) loci has been found to be associated with improved survival and development of immune-related adverse events (irAEs) among NSCLC patients treated with immunotherapy. Here, we investigated the effect of germline HLA-I/-II on clinical outcomes among NSCLC patients treated with first-line pembrolizumab in combination with chemotherapy.

METHOD

We prospectively recruited patients with NSCLC who were commencing first-line pembrolizumab in combination with chemotherapy. DNA from white blood cells was used for high-resolution HLA-I/II typing.

RESULTS

Of the 65 patients recruited, 53 complied with the inclusion criteria. We did not find an association between HLA-I/-II homozygosity and clinical outcome among the studied population. However, the presence of HLA-A01 was associated with unfavourable PFS (HR = 2.32, 95%CI 1.13-4.77, p = 0.022) and worsening OS (HR = 2.86, 95%CI 1.06-7.70, p = 0.038). The presence of HLA-B27 was associated with improved PFS (HR = 0.35, 95%CI 0.18-0.71, p = 0.004) and trends toward improving OS. None of the HLA-I supertypes were associated with the development or worsening of irAEs.

CONCLUSIONS

The absence of association between genomic HLA-I/-II homozygosity and clinical outcome among patients with advanced NSCLC treated with pembrolizumab in combination with chemotherapy might reflect a diminished role for HLA molecules among patients with low or no PD-L1. HLA-A01 and HLA-B27 might have a role in predicting clinical outcomes among this cohort of patients. Further studies are needed to explore biomarkers for this group of patients.

Human leukocyte antigen evolutionary divergence as a novel risk factor for donor selection in acute lymphoblastic leukemia patients undergoing haploidentical hematopoietic stem cell transplantation

Introduction

The human leukocyte antigen (HLA) evolutionary divergence (HED) reflects immunopeptidome diversity and has been shown to predict the response of tumors to immunotherapy. Its impact on allogeneic hematopoietic stem cell transplantation (HSCT) is controversial in different studies.

Methods

In this study, we retrospectively analyzed the clinical impact of class I and II HED in 225 acute lymphoblastic leukemia patients undergoing HSCT from related haploidentical donors. The HED for recipient, donor, and donor-recipient pair was calculated based on Grantham distance, which accounts for variations in the composition, polarity, and volume of each amino acid within the peptide-binding groove of two HLA alleles. The median value of HED scores was used as a cut-off to stratify patients with high or low HED.

Results

The class I HED for recipient (R_HEDclass I) showed the strongest association with cumulative incidence of relapse (12.2 vs. 25.0%, P = 0.00814) but not with acute graft-versus-host disease. The patients with high class II HED for donor-recipient (D/R_HEDclass II) showed a significantly higher cumulative incidence of severe aGVHD than those with low D/R_HEDclass II (24.0% vs. 6.1%, P = 0.0027). Multivariate analysis indicated that a high D/R_HEDclass II was an independent risk factor for the development of severe aGVHD (P = 0.007), and a high R_HEDclass I had a more than two-fold reduced risk of relapse (P = 0.028). However, there was no discernible difference in overall survival (OS) or disease-free survival (DFS) for patients with high or low HED, which was inconsistent with the previous investigation.

Discussion

While the observation are limited by the presented single center retrospective cohort, the results show that HED has poor prognostic value in OS or DFS, as well as the associations with relapse and aGVHD. In haploidentical setting, class II HED for donor-recipient pair (D/R_HEDclass II) is an independent and novel risk factor for finding the best haploidentical donor, which could potentially influence clinical practice if verified in larger cohorts.

The HLA-I landscape confers prognosis and antitumor immunity in breast cancer

Breast cancer is a highly heterogeneous disease with varied subtypes, prognoses and therapeutic responsiveness. Human leukocyte antigen class I (HLA-I) shapes the immunity and thereby influences the outcome of breast cancer. However, the implications of HLA-I variations in breast cancer remain poorly understood. In this study, we established a multiomics cohort of 1156 Chinese breast cancer patients for HLA-I investigation. We calculated four important HLA-I indicators in each individual, including HLA-I expression level, somatic HLA-I loss of heterozygosity (LOH), HLA-I evolutionary divergence (HED) and peptide-binding promiscuity (Pr). Then, we evaluated their distribution and prognostic significance in breast cancer subtypes. We found that the four breast cancer subtypes had distinct features of HLA-I indicators. Increased expression of HLA-I and LOH were enriched in triple-negative breast cancer (TNBC), while Pr was relatively higher in hot tumors within TNBCs. In particular, a higher Pr indicated a better prognosis in TNBCs by regulating the infiltration of immune cells and the expression of immune molecules. Using the matched genomic and transcriptomic data, we found that mismatch repair deficiency-related mutational signature and pathways were enriched in low-Pr TNBCs, suggesting that targeting mismatch repair deficiency for synthetic lethality might be promising therapy for these patients. In conclusion, we presented an overview of HLA-I indicators in breast cancer and provided hints for precision treatment for low-Pr TNBCs.

Tumor mutational burden for the prediction of PD-(L)1 blockade efficacy in cancer: challenges and opportunities

Tumor mutational burden (TMB) is a biomarker that measures the number of somatic mutations in a tumor's genome. TMB has emerged as a predictor of response to immune checkpoint inhibitors (ICIs) in various cancer types, and several studies have shown that patients with high TMB have better outcomes when treated with programmed death-ligand 1-based therapies. Recently, the Food and Drug Administration has approved TMB as a companion diagnostic for the use of pembrolizumab in solid tumors. However, despite its potential, the use of TMB as a biomarker for immunotherapy efficacy is limited by several factors. Here we review the limitations of TMB in predicting immunotherapy outcomes in patients with cancer and discuss potential strategies to optimize its use in the clinic.

Review - The impact of pharmacogenetics on the outcome of immune checkpoint inhibitors

The development of immune checkpoint inhibitors (ICIs) has a tremendous effect on the treatment options for multiple types of cancer. Nonetheless, there is a large interpatient variability in response, survival, and the development of immune-related adverse events (irAEs). Pharmacogenetics is the general term for germline genetic variations, which may cause the observed interindividual differences in response or toxicity to treatment. These genetic variations can either be single-nucleotide polymorphisms (SNPs) or structural variants, such as gene deletions, amplifications or rearrangements. For ICIs, pharmacogenetic variation in the human leukocyte antigen molecules has also been studied with regard to treatment outcome. This review presents a summary of the literature regarding the pharmacogenetics of ICI treatment, discusses the most important known genetic variations and offers recommendations on the application of pharmacogenetics for ICI treatment.

HLA-I Evolutionary Divergence Confers Response to PD-1 Blockade plus Chemotherapy in Untreated Advanced Non-Small Cell Lung Cancer

PURPOSE

PD-1 blockade plus chemotherapy has become the new standard of care in patients with untreated advanced non-small cell lung cancer (NSCLC), whereas predictive biomarkers remain undetermined.

EXPERIMENTAL DESIGN

We integrated clinical, genomic, and survival data of 427 NSCLC patients treated with first-line PD-1 blockade plus chemotherapy or chemotherapy from two phase III trials (CameL and CameL-sq) and investigated the predictive and prognostic value of HLA class I evolutionary divergence (HED).

RESULTS

High HED could predict significantly improved objective response rate (ORR), progression-free survival (PFS), and overall survival (OS) in those who received PD-1 blockade plus chemotherapy [in the CameL trial, ORR: 81.8% vs. 53.2%; P = 0.032; PFS: hazard ratio (HR), 0.47; P = 0.012; OS: HR, 0.40; P = 0.014; in the CameL-sq trial, ORR: 89.2% vs. 62.3%; P = 0.007; PFS: HR, 0.49; P = 0.005; OS: HR, 0.38; P = 0.002], but not chemotherapy. In multivariate analysis adjusted for PD-L1 expression and tumor mutation burden, high HED was independently associated with markedly better ORR, PFS, and OS in both trials. Moreover, the joint utility of HED and PD-L1 expression showed better performance than either alone in predicting treatment benefit from PD-1 blockade plus chemotherapy. Single-cell RNA sequencing of 58,977 cells collected from 11 patients revealed that tumors with high HED had improved antigen presentation and T cell-mediated antitumor immunity, indicating an inflamed tumor microenvironment phenotype.

CONCLUSIONS

These findings suggest that high HED could portend survival benefit in advanced NSCLC treated with first-line PD-1 blockade plus chemotherapy. See related commentary by Dimou, p. 4706.

Germline mechanisms of immunotherapy toxicities in the era of genome-wide association studies

Cancer immunotherapy has revolutionized the treatment of advanced cancers and is quickly becoming an option for early-stage disease. By reactivating the host immune system, immunotherapy harnesses patients' innate defenses to eradicate the tumor. By putatively similar mechanisms, immunotherapy can also substantially increase the risk of toxicities or immune-related adverse events (irAEs). Severe irAEs can lead to hospitalization, treatment discontinuation, lifelong immune complications, or even death. Many irAEs present with similar symptoms to heritable autoimmune diseases, suggesting that germline genetics may contribute to their onset. Recently, genome-wide association studies (GWAS) of irAEs have identified common germline associations and putative mechanisms, lending support to this hypothesis. A wide range of well-established GWAS methods can potentially be harnessed to understand the etiology of irAEs specifically and immunotherapy outcomes broadly. This review summarizes current findings regarding germline effects on immunotherapy outcomes and discusses opportunities and challenges for leveraging germline genetics to understand, predict, and treat irAEs.

The germline HLA-A02B62 supertype is associated with a PD-L1-positive tumour immune microenvironment and poor prognosis in stage I lung cancer

Background

Germline HLA class I molecule supertypes are shown to correlate with response to anti-PD-1 therapy. Here, we investigate the significance of germline HLA-A and HLA-B supertypes in tumour microenvironment of non-small-cell lung cancer.

Methods

Totally 278 NSCLC patients were collected retrospectively. HLA genotyping was conducted using next-generation sequencing. The evaluation of tumour-infiltrating lymphocytes was performed by multiplex immunohistochemistry assay. Correlations among HLA supertypes, tumour infiltrating lymphocytes, and clinicopathological characteristics were assessed.

Results

HLA-A03 and HLA-B62 were the supertypes with the highest proportions, at 69.1% and 52.2%, respectively. HLA-A02 or HLA-B62, but not HLA-A03, associated with higher PD-L1+ tumour and stromal cells levels, CD68+ cells, and CD68+PD-L1+ cells. Patients with both HLA-A02 and HLA-B62 supertypes displayed significantly higher PD-L1+ cells, CD68+ cells, and CD8+ cells levels than patients with other supertypes (P = 0.0301, P = 0.0479, P = 0.0192). These cells collectively constitute a hot but immunosuppressive tumour microenvironment. Accordingly, patients with both HLA-A02 and HLA-B62 supertypes had short progression-free survival after surgery (HR = 2.27, P = 0.0373).

Conclusions

The HLA-A02B62 supertype could serve as a possible indicator of poor prognosis in early-stage lung cancer. However, it may also act as a favorable prognostic factor for immunotherapy, given its association with a PD-L1-positive tumour microenvironment.

An immunogenic and oncogenic feature-based classification for chemotherapy plus PD-1 blockade in advanced esophageal squamous cell carcinoma

Although chemotherapy plus PD-1 blockade (chemo+anti-PD-1) has become the standard first-line therapy for advanced esophageal squamous cell carcinoma (ESCC), reliable biomarkers for this regimen are lacking. Here we perform whole-exome sequencing on tumor samples from 486 patients of the JUPITER-06 study and develop a copy number alteration-corrected tumor mutational burden that depicts immunogenicity more precisely and predicts chemo+anti-PD-1 efficacy. We identify several other favorable immunogenic features (e.g., HLA-I/II diversity) and risk oncogenic alterations (e.g., PIK3CA and TET2 mutation) associated with chemo+anti-PD-1 efficacy. An esophageal cancer genome-based immuno-oncology classification (EGIC) scheme incorporating these immunogenic features and oncogenic alterations is established. Chemo+anti-PD-1 achieves significant survival improvements in EGIC1 (immunogenic feature-favorable and oncogenic alteration-negative) and EGIC2 (either immunogenic feature-favorable or oncogenic alteration-negative) subgroups, but not the EGIC3 subgroup (immunogenic feature-unfavorable and oncogenic alteration-positive). Thus, EGIC may guide future individualized treatment strategies and inform mechanistic biomarker research for chemo+anti-PD-1 treatment in patients with advanced ESCC.

Human leukocyte antigen evolutionary divergence influences outcomes of paediatric patients and young adults affected by malignant disorders given allogeneic haematopoietic stem cell transplantation from unrelated donors

High genetic heterogeneity in the human leukocyte antigen (HLA) increases the likelihood of efficient immune response to pathogens and tumours. As measure of HLA diversity, HLA evolutionary divergence (HED) has been shown to predict the response of tumours to immunotherapy and haematopoietic stem cell transplantation (HSCT) in adults. We retrospectively investigated the association of HED with outcomes of 153 paediatric/young adults patients, treated for malignant disorders with HSCT from 9-10/10 HLA-matched unrelated donors. HED was calculated as pairwise genetic distance between alleles in patient HLA-A, -B, -C, -DRB1, -DQB1 and -DPB1, using the locus median to stratify patients with 'high' or 'low' HED. Patients with high HED-B and -DRB1 showed significantly improved disease-free survival (DFS), especially when combined (70.8% vs 53.7% p = 0.008). High HED-B + -DRB1 was also associated with improved overall survival (OS) (82.1 vs 66.4% p = 0.014), and concomitant reduction of non-relapse-mortality (5.1% vs 21.1% p = 0.006). The impact on OS and DFS of combined HED-B + -DRB1 was confirmed in multivariate analysis [hazard ratio (HR) 0.39, p = 0.009; and HR 0.45, p = 0.007 respectively]. Only high HED scores for HLA-DPB1 were associated, in univariate analysis, with reduced incidence of relapse (15.9% vs 31.1%, p = 0.03). These results support HED as prognostic marker in allogeneic HSCT and, if confirmed in larger cohorts, would allow its use to inform clinical risk and potentially influence clinical practice.

Translating the evolving molecular landscape of tumors to biomarkers of response for cancer immunotherapy

Immune checkpoint inhibitors (ICIs) have revolutionized cancer therapeutics, triggering studies to understand the molecular and cellular wiring of response and resistance. Our increased understanding of the underlying biology of response to ICI has enabled the investigation of tumor-intrinsic and -extrinsic features that may predict therapeutic outcomes. In parallel, liquid biopsy measurements of circulating tumor DNA (ctDNA) can be used to assess real-time molecular responses and guide clinical decisions during ICI. The combination of these approaches provides a deeper understanding of cancer biology, immunoediting, and evolution during ICI and promise to extend the utility of immunotherapies for patients with cancer.

Biomarkers and immunotherapy: where are we?

PURPOSE OF REVIEW

Here, we reviewed the recent breakthroughs in the understanding of predictive biomarkers for immune checkpoint inhibitors (ICI) treatment.

RECENT FINDINGS

ICI have revolutionized cancer therapy enabling novel therapeutic indications in multiple tumor types and increasing the probability of survival in patients with metastatic disease. However, in every considered tumor types only a minority of patients exhibits clear and lasting benefice from ICI treatment, and due to their unique mechanism of action treatment with ICI is also associated with acute clinical toxicities called immune related adverse events (irAEs) that can be life threatening. The approval of the first ICI drug has prompted many exploratory strategies for a variety of biomarkers and have shown that several factors might affect the response to ICI treatment, including tumors intrinsic factors, tumor microenvironment and tumor extrinsic or systemic factor. Currently, only three biomarkers programmed death-ligand 1 (PD-L1), tumor microenvironment and microsatellite instability had the US Food and Drug Administration-approbation with some limitations.

SUMMARY

The establishment of valid predictive biomarkers of ICI sensitivity has become a priority to guide patient treatment to maximize the chance of benefit and prevent unnecessary toxicity.

Integration of tumor extrinsic and intrinsic features associates with immunotherapy response in non-small cell lung cancer

The efficacy of immune checkpoint blockade (ICB) varies greatly among metastatic non-small cell lung cancer (NSCLC) patients. Loss of heterozygosity at the HLA-I locus (HLA-LOH) has been identified as an important immune escape mechanism. However, despite HLA-I disruptions in their tumor, many patients have durable ICB responses. Here we seek to identify HLA-I-independent features associated with ICB response in NSCLC. We use single-cell profiling to identify tumor-infiltrating, clonally expanded CD4⁺ T cells that express a canonical cytotoxic gene program and NSCLC cells with elevated HLA-II expression. We postulate cytotoxic CD4⁺ T cells mediate anti-tumor activity via HLA-II on tumor cells and augment HLA-I-dependent cytotoxic CD8⁺ T cell interactions to drive ICB response in NSCLC. We show that integrating tumor extrinsic cytotoxic gene expression with tumor mutational burden is associated with longer time to progression in a real-world cohort of 123 NSCLC patients treated with ICB regimens, including those with HLA-LOH.

Some cancer patients with impaired HLA-I still respond to immunotherapy. Here the authors combine a cytotoxic gene signature from CD4+ and CD8+ T cells with tumor mutational burden to predict immunotherapy response in NSCLC patients, including those with HLA-LOH.

'Know thyself' - host factors influencing cancer response to immune checkpoint inhibitors

Immune checkpoint inhibitors (ICIs) have revolutionised oncology and are now standard-of-care for the treatment of a wide variety of solid neoplasms. However, tumour responses remain unpredictable, experienced by only a minority of ICI recipients across malignancy types. Therefore, there is an urgent need for better predictive biomarkers to identify a priori the patients most likely to benefit from these therapies. Despite considerable efforts, only three such biomarkers are FDA-approved for clinical use, and all rely on the availability of tumour tissue for immunohistochemical staining or genomic assays. There is emerging evidence that host factors - for example, genetic, metabolic, and immune factors, as well as the composition of one's gut microbiota - influence the response of a patient's cancer to ICIs. Tantalisingly, some of these factors are modifiable, paving the way for co-therapies that may enhance the therapeutic index of these treatments. Herein, we review key host factors that are of potential biomarker value for response to ICI therapy, with a particular focus on the proposed mechanisms for these influences. © 2022 The Authors. The Journal of Pathology published by John Wiley & Sons Ltd on behalf of The Pathological Society of Great Britain and Ireland.

Next-generation sequencing: unraveling genetic mechanisms that shape cancer immunotherapy efficacy

Immunity is governed by fundamental genetic processes. These processes shape the nature of immune cells and set the rules that dictate the myriad complex cellular interactions that power immune systems. Everything from the generation of T cell receptors and antibodies, control of epitope presentation, and recognition of pathogens by the immunoediting of cancer cells is, in large part, made possible by core genetic mechanisms and the cellular machinery that they encode. In the last decade, next-generation sequencing has been used to dissect the complexities of cancer immunity with potent effect. Sequencing of exomes and genomes has begun to reveal how the immune system recognizes “foreign” entities and distinguishes self from non-self, especially in the setting of cancer. High-throughput analyses of transcriptomes have revealed deep insights into how the tumor microenvironment affects immunotherapy efficacy. In this Review, we discuss how high-throughput sequencing has added to our understanding of how immune systems interact with cancer cells and how cancer immunotherapies work.

Coming of Age: Human Genomics and the Cancer-Immune Set Point

Cancer is largely a disease of the tumor cell genome. As a result, the majority of genetics research in oncology has concentrated on the role of tumor somatic mutations, as well as inherited risk variants, in disease susceptibility and response to targeted treatments. The advent and success of cancer immunotherapies, however, have opened new perspectives for the investigation of the role of inherited genetic variation in codetermining outcome and safety. It is increasingly likely that the entirety of germline genetic variation involved in regulating immune responses accounts for a significant fraction of the observed variability in responses to cancer immunotherapies. Although germline genetic data from patients treated with cancer immunotherapies are still scarce, this line of research benefits from a vast body of knowledge derived from studies into autoimmune and infectious disease phenotypes, thus not requiring a start from a blank slate. Here, we discuss how a thorough investigation of genomic variation relevant for individuals' variability in (auto)immune responses can contribute to the discovery of novel treatment approaches and drug targets, and yield predictive biomarkers to stratify cancer patient populations in precision and personalized medicine settings.

Genetic variation in antigen presentation and cancer immunotherapy

Human leukocyte antigen (HLA) molecules are critical mediators of anti-tumor immune responses. In this issue of Immunity,Chhibber et al. (2021) challenge previous associations between germline HLA zygosity and immunotherapy outcomes, demonstrating that germline HLA genotypes and diversity alone are not independent biomarkers of anti-PD1 clinical efficacy.