Utility of expression of 4-hydroxynonenal tested by immunohistochemistry for cervical cancer.

Introduction: Cervical cancer (CC) is a leading cause of mortality in women around the world, with the highest incidence rate still being in developing countries. The most common aetiological factor is infection with high-risk human papilloma virus viral strains. Oxidative stress through generation of reactive oxygen species leads to lipid peroxidation and DNA damage. Studies show that reactive lipid electrophiles such as 4-hydroxynonenal (4-HNE) produced in the process play an important role in cancer signalling pathways and are a good biomarker for oxidative stress. We aim to investigate the prognostic role of 4-HNE as a biomarker for oxidative stress in patients in early and advanced stages of CC measured by immunohistochemistry. Material and methods: This is a retrospective study of 69 patients treated at our Department of Oncogynaecology. Paraffin embedded tumour tissues were immunohistochemically tested for the levels of expression of 4-HNE. The results for H-score, Allred score, and combined score were investigated for association with tumour size, lymph node status, andInternational Federation of Gynaecology and Obstetrics stage. Results: 4-hydroxynonenal showed higher expression in more advanced stages of CC and in cases with involved lymph nodes. Tumour size was not associated with the levels of 4-HNE. Conclusions: To best of our knowledge, this is the first study to use immunohistochemistry to examine the expression of 4-HNE as a prognostic factor in CC. The 3 score systems showed similar results. The pattern of 4-HNE histological appearance is dependent on the histological origin of cancer and is not universal.

Relative Risk of Death in Bulgarian Cancer Patients during the Initial Waves of the COVID-19 Pandemic.

BACKGROUND: The COVID-19 pandemic has led to millions of documented deaths worldwide, with diverse distribution among countries. Surprisingly, Bulgaria, a middle-income European Union member state, ranked highest in COVID-19 mortality. This study aims to assess whether Bulgarian cancer patients experienced a higher relative risk (RR) of death compared to the general Bulgarian population during the pandemic. MATERIALS AND METHODS: Data from the Bulgarian National Statistical Institute and the Bulgarian National Cancer Registry were analyzed to estimate monthly RR of death in cancer patients compared to the general population before and during the first two years of the pandemic. The impact of the COVID-19 waves and predominant SARS-CoV-2 variants on RR was evaluated on various cancer types and age groups using a multiple linear regression approach. RESULTS: During the COVID-19 waves, both the general population and cancer patients experienced a significant increase in mortality rates. Surprisingly, the RR of death in cancer patients was lower during pandemic waves. The results from the statistical modeling revealed a significant association between the COVID-19 waves and reduced RR for all cancer patients. Notably, the effect was more pronounced during waves associated with the Alpha and Delta variants. The results also showed varying impacts of the COVID-19 waves on RR when we analyzed subsamples of data grouped depending on the cancer type, age and sex. CONCLUSIONS: Despite increased overall mortality in Bulgarian cancer patients during the pandemic, the RR of death was lower compared to the Bulgarian general population, indicating that protective measures were relatively effective in this vulnerable group. This study underscores the importance of implementing and encouraging preventive measures, especially in cancer patients, to mitigate the impact of future viral pandemics and reduce excess mortality.

Possible impact of HLA class I and class II on malignancies driven by a single germ-line BRCA1 mutation.

This study provides the first immunogenetic preliminary evidence that specific human leucocyte antigen (HLA) class I and class II alleles and haplotypes may be relevant for BRCA1 c.5263_5264insC driven oncogenesis. Observed HLA associations might have practical implications for establishment of predictive markers for the response to immunotherapies in malignancies driven by this germ-line mutation.

The role of non-classical and chain-related human leukocyte antigen polymorphisms in laryngeal squamous cell carcinoma.

BACKGROUND: Laryngeal squamous cell carcinoma (LSCC) is the major pathological subtype of laryngeal cancer. It has been shown that alterations of the expression of non-classical human leukocyte antigens (HLA) and the chain-related MIC molecules by malignant cells can lead to escape from the immune system control and certain allele variants may participate in immune editing and therefore be associated with modulation of cancer risk. The aim of the present study was to investigate the role of non-classical HLA class Ib and chain-related MIC polymorphisms, determined at the allelic level by next-generation sequencing (NGS), in patients from the Bulgarian population, diagnosed with LSCC. MATERIALS AND METHODS: In the present study DNA samples from 48 patients with LSCC were used. Data was compared to 63 healthy controls analysed in previous studies. HLA genotyping was performed by using the AlloSeq Tx17 early pooling protocol and the library preparation AlloSeq Tx17 kit (CareDx). Sequencing was performed on MiniSeq sequencing platform (Illumina) and HLA genotypes were assigned with the AlloSeq Assign analysis software v1.0.3 (CareDx) and the IPD-IMGT/HLA database 3.45.1.2. RESULTS: The HLA disease association tests revealed a statistically significant predisposing association of HLA-F*01:01:02 (Pc = 0.0103, OR = 24.0194) with LSCC, while HLA-F*01:01:01 (Pc = 8.21e-04, OR = 0.0485) has a possible protective association. Additionally we observed several haplotypes with statistically significant protective and predisposing associations. The strongest association was observed for F*01:01:01-H*01:01:01 (P = 0.0054, haplotype score=-2.7801). CONCLUSION: Our preliminary study suggests the involvement of HLA class Ib in cancer development and the possible role of the shown alleles as biomarkers of LSCC.

The effects of ROMO1 on cervical cancer progression.

INTRODUCTION: More than 95% of the cases of Cervical cancer (CC) are now linked to infection with Human papilloma virus (HPV) but the infection alone is not sufficient for starting the oncogenesis. Reactive Oxygen Species (ROS) can promote CC cancerogenesis. ROMO1 is a protein that regulates the production of intracellular ROS and influences cancer cell invasion and proliferation. We aimed to investigate the impact of ROS in CC progression, measured by the expression of ROMO1. METHODS AND MATERIALS: This is a retrospective study of 75 patients treated at the Department of Oncogynecology, Medical University of Pleven, Bulgaria. Paraffin embedded tumor tissues were immunohistochemically tested for the levels of expression of ROMO1. The results for both Allred score and H-score were investigated for association with tumor size, lymph node status and FIGO stage. RESULTS: Levels of ROMO1 were significantly higher in FIGO1 stage compared to FIGO2 and FIGO3 according to both scores (for H-score FIGO1 vs FIGO2 p = 0.00012; FIGO 1 vs FIGO3 p = 0.0008; for Allred score FIGO1 vs FIGO2, p = 0.0029; FIGO1 vs FIGO3 (p = 0.012). Statistically significant difference was found according to the H-score between patients with and without metastatic lymph nodes (p = 0.033). CONCLUSION: To the best of our knowledge this is the first study testing immunohistochemically the expression of ROMO1 for CC progression. The levels of ROMO1 were significantly higher in early stage tumors compared to advanced. Bearing in mind that only 75 patients were tested, further studies are required to evaluate the value of ROS in CC.

A Novel Two-Gene Expression-Based Prognostic Score in Malignant Pleural Mesothelioma.

BACKGROUND: Malignant pleural mesothelioma (MPM) is a rare cancer type with an increasing incidence worldwide. We aimed to develop a rational gene expression-based prognostic score in MPM using publicly available datasets. METHODS: We developed and validated a two-gene prognostic score (2-PS) using three independent publicly available gene expression datasets. The 2-PS was built using the Robust Likelihood-Based Survival Modeling with Microarray Data method. RESULTS: We narrowed down the model building to the analysis of 179 genes, which have been shown previously to be of importance to MPM development. Our statistical approach showed that a model including two genes (GOLT1B and MAD2L1) was the best predictor for overall survival (OS) (p < 0.0001). The binary score based on the median of the continuous score stratified the patients into low and high score groups and also showed statistical significance in uni- and multivariate models. The 2-PS was validated using two independent transcriptomic datasets. Furthermore, gene set enrichment analysis using training and validation datasets showed that high score patients had distinct gene expression profiles. Our 2-PS also showed a correlation with the estimated infiltration by some immune cell fractions such as CD8+ T cells and M1/2 macrophages. Finally, 2-PS correlated with sensitivity or resistance to some commonly used chemotherapeutic drugs. CONCLUSION: This is the first study to demonstrate good performance of only two-gene expression-based prognostic scores in MPM. Our initial approach for features selection allowed for an increased likelihood for the predictive value of the developed score, which we were also able to demonstrate.

Infiltration by Intratumor and Stromal CD8 and CD68 in Cervical Cancer.

Background and Objectives: The tumor microenvironment (TME) plays a major role in neoplastic development. Various types of cells can be found in the TME. These cells can be classified into two groups, immunosuppressive and immunostimulatory types, depending on the function they perform in the antitumor immune response (IR). By interacting both with each other and with tumor cells, different immune mechanisms are activated or inhibited, which can suppress or promote the development and progression of cervical cancer (CC). Our aim was to investigate some of the main components of the cellular immune response in TME-tumor-infiltrating cytotoxic T cells (Tc, CD8+) and tumor-associated macrophages (TAMs, CD68+)-in patients with CC. Materials and Methods: We analyzed 72 paraffin-embedded tumor tissues of patients diagnosed and treated at Medical University Pleven, Bulgaria. Patients were classified according to the 2018 FIGO (International Federation of Gynaecology and Obstetrics) classification. From each patient, we selected one histological slide with hematoxylin eosin staining. In a microscopic evaluation, CD8+ T lymphocytes and CD68+-positive macrophages were counted in the tumor and stroma of five randomly selected fields at ×40 magnification (HPF). We analyzed the relationship between intratumoral and stromal CD8 and CD68 expression and FIGO stage and N status. Results: There was no significant association between the expression levels of intratumoral and stromal CD68+ cells in the different FIGO stages and according to the lymph nodes' involvement. For CD8+ cells, the association of stromal infiltration was also not found, but T intratumor infiltration was associated with a higher FIGO stage, despite the fact that the results did not reach significance (p = 0.063, Fisher test). Intratumoral CD8+ cells were significantly associated with positive N status, (p = 0.035). Discussion: The separation of tumor-infiltrating cytotoxic T cells and tumor-associated macrophages into intratumoral and stromal is inconsequential. In our study, the level of infiltration of CD68+ cells in tumors and stromata was not significantly associated with tumor progression or lymph node involvement. The results were different for CD8+ cells, in which levels of infiltration were associated with lymph nodes' statuses. Conclusions: The separate evaluation of CD68+ immune cells in the TME as intratumoral and stromal is not beneficial for defining prognoses, since the presence of these cells is not associated with the patient's stage. In our study, the presence of CD8+ cells was significantly associated with lymph node metastases. The prognostic value of the obtained results can be enriched with an additional study of the lymphocyte phenotype, including B and other subtypes of T lymphocytes, NK cells, as well as molecules involved in the immune response, such as HLA subtypes.

Exploration of the role of NKG2D ligands MICA and MICB in JAK2 V617F-positive myeloproliferative neoplasms.

JAK2 V617F-driven myeloproliferative neoplasms (MPNs) can escape immune surveillance through PD-L1 up-regulation and HLA class I pathway down-regulation. To complement these data we assessed the role of major histocompatibility complex class I-related genes (MICA and MICB) in JAK2 V617F+ MPNs. Using high resolution genotyping we identified two protective alleles, MICA*008:01 and MICA*016. MPN patients had significantly higher levels of soluble sMICA molecules. Peripheral blood JAK2 V617F+ granulocytes had higher surface expression of MICB but did not differ in the amount of MICA and MICB transcripts from normal granulocytes. MICA and MICB genes were significantly down-regulated in JAK2 V617F+ CD34+ cells from primary myelofibrosis patients in comparison to normal CD34+ hematopoietic stem cells. These data suggest minor but significant role of MICA and MICB genes in the pathogenesis of MPNs. It is also possible that MICA targeting approaches could be of clinical benefit for some of those patients.

Seasonal Pattern of Cerebrovascular Fatalities in Cancer Patients.

Cancer patients are at increased risk of cerebrovascular events. The incidence of those events and the associated mortality are known to follow a seasonal pattern in the general population. However, it is unclear whether cerebrovascular mortality in cancer patients has seasonal variation. To address this question, we performed a retrospective analysis of the seasonality of deaths due to the fact of cerebrovascular diseases among patients with first primary malignancy registered between 1975 and 2016 in the SEER database. The presence of seasonality in death rates was modeled using the cosinor approach assuming a circa-annual pattern. A significant seasonal pattern with a peak in the first half of November was identified in all patient groups. The same peak was observed in almost all subgroups of patients defined based on demographic characteristics. However, not all entity-defined subgroups showed a seasonal pattern, which might be explained by the different pathologic processes affecting the circulatory system in each cancer type. Based on our findings, one can propose that the active monitoring of cancer patients for cerebrovascular events from the late autumn and during the winter can help in the reduction of mortality in this patient population.

Reactivity Graph Yields Interpretable IgM Repertoire Signatures as Potential Tumor Biomarkers.

Combining adaptive and innate immunity induction modes, the repertoire of immunoglobulin M (IgM) can reflect changes in the internal environment including malignancies. Previously, it was shown that a mimotope library reflecting the public IgM repertoire of healthy donors (IgM IgOme) can be mined for efficient probes of tumor biomarker antibody reactivities. To better explore the interpretability of this approach for IgM, solid tumor-related profiles of IgM reactivities to linear epitopes of actual tumor antigens and viral epitopes were studied. The probes were designed as oriented planar microarrays of 4526 peptide sequences (as overlapping 15-mers) derived from 24 tumor-associated antigens and 209 cancer-related B cell epitopes from 30 viral antigens. The IgM reactivity in sera from 21 patients with glioblastoma multiforme, brain metastases of other tumors, and non-tumor-bearing neurosurgery patients was thus probed in a proof-of-principle study. A graph representation of the binding data was developed, which mapped the cross-reactivity of the mixture of IgM (poly)specificities, delineating different antibody footprints in the features of the graph-neighborhoods and cliques. The reactivity graph mapped the major features of the IgM repertoire such as the magnitude of the reactivity (titer) and major cross-reactivities, which correlated with blood group reactivity, non-self recognition, and even idiotypic specificities. A correlation between an aspect of this image of the IgM IgOme, namely, small cliques reflecting rare self-reactivities and the capacity of subsets of the epitopes to separate the diagnostic groups studied was found. In this way, the graph representation helped the feature selection in its filtering step and provided reduced feature sets, which, after recursive feature elimination, produced a classifier containing 51 peptide reactivities separating the three diagnostic groups with an unexpected efficiency. Thus, IgM IgOme approaches to repertoire studies is greatly augmented when self/viral antigens are used and the data are represented as a reactivity graph. This approach is most general, and if it is applicable to tumors in immunologically privileged sites, it can be applied to any solid tumors, for instance, breast or lung cancer.

The relevance of HLA class II genes in JAK2 V617F-positive myeloproliferative neoplasms.

In the present study we analyzed the relevance of HLA class II in JAK2 V617F-positive (JAK2 V617F+) myeloproliferative neoplasms (MPNs) focusing on genotype diversity, associations with specific alleles and haplotypes and the level of gene expression. One hundred and thirty-nine JAK2 V617F+ MPN patients and 1083 healthy controls, typed by Next generation sequencing (NGS) were included in the study. Multivariate generalized linear models with age as a covariate were applied for analysis of HLA-II allele and haplotype associations. Publicly available gene expression datasets were used to analyze HLA-II pathway genes expression in CD34+ stem cells (SCs) from MPN patients and healthy controls. We did not observe differences in HLA evolutionary divergence (HED) between JAK2 V617F+ MPNs and healthy controls. Two alleles: HLA-DPB1*03:01, DQB1*04:02 and 4 haplotypes: DPB1*02:01-DQA1*05:05-DQB1*03:01-DRB1*11:01, DPB1*04:02-DQA1*05:05-DQB1*03:01-DRB1*11:03, DPB1*02:01-DQA1*01:04-DQB1*05:03-DRB1*14:04, and DPB1*04:01-DQA1*03:01-DQB1*03:02-DRB1*04:01 had significantly lower frequency in MPN patients compared to controls. Additionally, we observed HLA-II alleles and haplotypes with statistically higher frequencies in JAK2 V617F+ patients. Differential gene expression analysis showed down-regulation of HLA-DRB1, -DRA, -DMA, -DMB, -DOA,-DRB4, CIITA, and CD74 genes in JAK2 V617F+ MPN CD34+ SCs as compared to normal CD34 + SCs. In conclusion, this study provides evidence for the pleiotropic effects of HLA-II genes in JAK2 V617F-driven MPNs.

Seasonality of Deaths Due to Heart Diseases among Cancer Patients.

Background and Objectives: Cancer patients are at increased short- and long-term risk of cardiac toxicity and mortality. It is well-known that cardiac morbidity and mortality follows a seasonal pattern. Here we address the question of whether heart disease-related fatalities among cancer patients also follow a seasonal pattern. Materials and Methods: We performed a retrospective analysis of seasonality of deaths due to heart diseases (n = 503,243) in patients with newly diagnosed cancer reported during the period from 1975 to 2016 in the US's largest cancer registry-the Surveillance, Epidemiology, and End Results (SEER) database. Seasonality was assessed through a classical cosinor model assuming a single annual peak. Results: We identified a significant seasonal peak in the first half of November. A peak with identical features was for all subgroups of patients defined based on demographic characteristics. This was also the case when analysis was performed on subgroups defined by the type of malignancy. Only patients with acute leukemias, pancreatic cancer and nervous system malignancies did not have a seasonal pattern in heart disease-related fatalities. Conclusion: the rate of heart disease-related fatalities after cancer diagnosis follows a seasonal pattern similar to that observed for the general population, albeit with an earlier peak in November. This suggests that close monitoring of the cardiovascular system in cancer survivors must be particularly active from late autumn and during the entire winter period.

Restriction of the Global IgM Repertoire in Antiphospholipid Syndrome.

The typical anti-phospholipid antibodies (APLA) in the anti-phospholipid syndrome (APS) are reactive with the phospholipid-binding protein ß2GPI as well as a growing list of other protein targets. The relation of APLA to natural antibodies and the fuzzy set of autoantigens involved provoked us to study the changes in the IgM repertoire in APS. To this end, peptides selected by serum IgM from a 7-residue linear peptide phage display library (PDL) were deep sequenced. The analysis was aided by a novel formal representation of the Igome (the mimotope set reflecting the IgM specificities) in the form of a sequence graph. The study involved women with APLA and habitual abortions (n=24) compared to age-matched clinically healthy pregnant women (n=20). Their pooled Igomes (297 028 mimotope sequences) were compared also to the global public repertoire Igome of pooled donor plasma IgM (n=2 796 484) and a set of 7-mer sequences found in the J regions of human immunoglobulins (n=4 433 252). The pooled Igome was represented as a graph connecting the sequences as similar as the mimotopes of the same monoclonal antibody. The criterion was based on previously published data. In the resulting graph, identifiable clusters of vertices were considered related to the footprints of overlapping antibody cross-reactivities. A subgraph based on the clusters with a significant differential expression of APS patients' mimotopes contained predominantly specificities underrepresented in APS. The differentially expressed IgM footprints showed also an increased cross-reactivity with immunoglobulin J regions. The specificities underexpressed in APS had a higher correlation with public specificities than those overexpressed. The APS associated specificities were strongly related also to the human peptidome with 1 072 mimotope sequences found in 7 519 human proteins. These regions were characterized by low complexity. Thus, the IgM repertoire of the APS patients was found to be characterized by a significant reduction of certain public specificities found in the healthy controls with targets representing low complexity linear self-epitopes homologous to human antibody J regions.

Prognostic Utility of CD47 in Cancer of the Uterine Cervix and the Sensitivity of Immunohistochemical Scores.

INTRODUCTION: Cancer of the uterine cervix (CUC) is still one of the most frequent oncological diagnoses in women. The specific interactions between the tumor cells of CUC and the cells and tissues in the tumor microenvironment can affect cancer cells' invasive and metastatic potential and can modulate tumor's progression and death. CD47 is a trans-membranous immunoglobulin, expressed in many cells. It protects the cells from being destroyed by the circulating macrophages. AIM: We aimed to evaluate the prognostic role of CD47 expressed in the tumor tissues of patients with CUC for tumor progression and to find the most sensitive immunohistochemical score for defining the cut-off significantly associated with tumor biology and progression. MATERIALS AND METHODS: Paraffin-embedded tumor tissues from 86 patients with CUC were included in the study. Clinico-morphological data for patients, such as age and stage at diagnosis according to FIGO and TNM classification, were obtained from the hospital electronic medical records. Immunohistochemical staining was performed with rabbit recombinant monoclonal CD47 antibody (Clone SP279). The final result was interpreted based on three reporting models in immunohistochemistry: H-score, Allred score and combined score. RESULTS: The expression of CD47 was higher in tumors limited in the cervix compared with those invading other structures, and it did not depend on the nodal status. The results of immunohistochemical staining were similar regardless of which immunohistochemical method was used. The most significant correlation with TNM stage was observed with the H-score (p = 0.00018). The association with the Allred and combined score was less significant, with p values of 0.0013 and 0.0002, respectively. CONCLUSION: The expression of CD47 in the cancer cells is prognostic for tumor invasion in the surrounding structures, independent of lymph node engagement. The H-score is the most sensitive immunohistochemical score to describe tumor stage. To the best of our knowledge, this is the first study evaluating the significance of CD47 expression in CUC.

Bringing Together the Power of T Cell Receptor Mimic and Bispecific Antibodies for Cancer Immunotherapy: Still a Long Way to Go.

Antibody-based cancer immunotherapy has revolutionized oncology. The first successful therapeutic antibodies relied on eliciting immune-mediated cytotoxicity (rituximab) or modulation of intracellular signaling (trastuzumab). Further attempts to enhance the antitumor effects led to the development of immunoconjugates with radioactive or cytotoxic compounds (tositumomab, brentuximab vedotin). Another line of research led to the bispecific antibodies that can enhance the formation of immunological synapse between cancer and cytotoxic T cells (blinatumomab). Despite the constant advances in design and production, the application of monoclonal antibodies in cancer treatment remains limited by the presence of specific cell surface markers. A rational approach to target intracellular cancer antigens was proposed almost two decades ago by the development of anti-peptide human leukocyte antigen (HLA) complex (T cell receptor-like/mimic) antibodies. They could recognize specifically cancer neoantigens expressed in the context of specific HLA molecules theoretically providing unprecedented specificity. Furthermore, they can be developed in a semigeneric format, that is, to target common neoantigens expressed in the context of common HLA molecules. It is rationale to expect that the development of such antibodies in the format of bispecific antibody constructs can bring together the power of specific antibody-based recognition and that of T cell-mediated lysis. There are already some preliminary reports that suggest such constructs would be an achievable goal. In this brief review, we discuss some of the successful preclinical developments in the field and the major challenges that are yet to be addressed.

Associations of high-resolution-typing-defined MICA and MICB polymorphisms, and the levels of soluble MICA and MICB with Oral Squamous Cell Carcinoma in Bulgarian patients.

BACKGROUND: Oral Squamous Cell Carcinoma (OSCC) is a malignancy characterized by an aggressive tumor growth and significant mortality. Clarifying mechanisms responsible for immunomodulation are among the main challenges for the development of personalized approaches for the management of patients with Oral Squamous Cell Carcinoma. The aim of the present study was to analyze the relevance of MICA and MICB to Oral Squamous Cell Carcinoma pathogenesis focusing on allele polymorphisms and the levels of soluble MICA and MICB molecules. MATERIALS AND METHODS: 73 patients diagnosed with Oral Squamous Cell Carcinoma and 149 healthy controls from the Bulgarian population were included in the study. MICA and MICB polymorphism was analyzed at high-resolution level using Next-Generation Sequencing. Serum levels of soluble MICA and MICB molecules were measured by ELISA. RESULTS: Our results show significant protective association with MICB*002:01, while relatively rare alleles MICB*018, *019, and *020 were observed with statistically significant increased frequency in Oral Squamous Cell Carcinoma patients compared to controls. Additionally, a predisposing association was observed for MICA*008:01-MICB*019 haplotype. A correlation analysis between functionally relevant MICA polymorphisms and sMICA showed that homozygosity for MICA-A5.1 or 129Val in OSCC patients was associated with significantly higher serum levels of sMICA. CONCLUSION: This is the first study showing significant associations between MICB alleles and Oral Squamous Cell Carcinoma and suggesting the possible role of MICB in immunosurveillance in Oral Squamous Cell Carcinoma development. Observed correlations between the levels of soluble MICA molecules and functionally relevant polymorphisms might represent a further step toward a better understanding of molecular mechanisms of Oral Squamous Cell Carcinoma and developing strategies for therapeutic targeting harnessing effective immunosurveillance.

HLA genotyping meets response to immune checkpoint inhibitors prediction: A story just started.

The implementation of the immune checkpoint blockade as a therapeutic option in contemporary oncology is one of the significant immunological achievements in the last century. Constantly accumulating evidence suggests that the response to immune checkpoint inhibitors (ICIs) is not universal. Therefore, it is critical to identify determinants for response, resistance and adverse effects of immune checkpoint therapy that could be developed as prognostic and predictive markers. Recent large scale analyses of cancer genome data revealed the key role of HLA class I and class II molecules in cancer immunoediting, and it appears that HLA diversity can predict response to ICIs. In the present review, we summarize the emerging data on the role of HLA germline variations as a marker for response to ICIs.