VISTA: a novel immunotherapy target for normalizing innate and adaptive immunity

IGSF11 and VISTA: a pair of promising immune checkpoints in tumor immunotherapy

Immunotherapy has become the major treatment for tumors in clinical practice, but some intractable problems such as the low response rate and high rates of immune-related adverse events still hinder the progress of tumor immunotherapy. Hence, it is essential to explore additional immunotherapy treatment targets. In this review, we focus on the structure, expression and expression-related mechanisms, interactions, biological functions and the progress in preclinical/clinical research of IGSF11 and VISTA in tumors. We cover the progress in recent research with this pair of immune checkpoints in tumor immune regulation, proliferation, immune resistance and predictive prognosis. Both IGSF11 and VISTA are highly expressed in tumors and are modulated by various factors. They co-participate in the functional regulation of immune cells and the inhibition of cytokine production. Besides, in the downregulation of IGSF11 and VISTA, both inhibit the growth of some tumors. Preclinical and clinical trials all emphasize the predictive role of IGSF11 and VISTA in the prognosis of tumors, and that the predictive role of the same gene varies from tumor to tumor. At present, further research is proving the enormous potential of IGSF11 and VISTA in tumors, and especially the role of VISTA in tumor immune resistance. This may prove to be a breakthrough to solve the current clinical immune resistance, and most importantly, since research has focused on VISTA but less on IGSF11, IGSF11 may be the next candidate for tumor immunotherapy.

Modulation of Lymphocyte Functions in the Microenvironment by Tumor Oncogenic Pathways

Despite the broad application of different immunotherapeutic strategies for the treatment of solid as well as hematopoietic cancers, the efficacy of these therapies is still limited, with only a minority of patients having a long-term benefit resulting in an improved survival rate. In order to increase the response rates of patients to the currently available immunotherapies, a better understanding of the molecular mechanisms underlying the intrinsic and/or extrinsic resistance to treatment is required. There exist increasing evidences that activation of different oncogenic pathways as well as inactivation of tumor suppressor genes (TSG) in tumor cells inhibit the immune cell recognition and influegnce the composition of the tumor microenvironment (TME), thus leading to an impaired anti-tumoral immune response. A deeper understanding of the link between the tumor milieu and genomic alterations of TSGs and oncogenes is indispensable for the optimization of immunotherapies and to predict the patients’ response to these treatments. This review summarizes the role of different cancer-related, oncogene- and TSG-controlled pathways in the context of anti-tumoral immunity and response to different immunotherapies.

Macrophage Differentiation and Polarization Regulate the Release of the Immune Checkpoint Protein V-Domain Ig Suppressor of T Cell Activation

Recently, the V-domain immunoglobulin suppressor of T-cell activation (VISTA) was identified as a negative immune checkpoint regulator (NCR) that is mainly expressed in hematopoietic cells. Preclinical studies have shown that VISTA blockade results in impeded tumor growth and improved survival. Nevertheless, little is known about the physiological role of VISTA expression in macrophages. This study focused on the differential expression of VISTA in human monocytes and macrophages in order to elucidate a putative role of VISTA regulation upon macrophage polarization and activation. We observed that human peripheral monocytes constitutively release soluble VISTA, which was regulated via matrix metalloproteinases. However, monocyte stimulation with cytokines that induce macrophage differentiation, such as granulocyte-macrophage colony–stimulating (GM-CSF) and macrophage colony-stimulating factor (M-CSF), substantially reduced soluble VISTA release. VISTA release was further affected by various pro- and anti-inflammatory stimuli that led to macrophage polarization, where activated M1 macrophages generally released more VISTA than M2 macrophages. Additionally, we observed that stimulation of activated macrophages with the toll-like receptor 4 ligand lipopolysaccharide (LPS) led to a further decrease of soluble VISTA release. Moreover, we found that soluble VISTA impairs T cell cytotoxic activity but did not induce their programmed death. Our results suggest that VISTA is constantly produced and released in the peripheral blood where it may contribute to peripheral tolerance.

Targeting protein kinases benefits cancer immunotherapy

Small-molecule kinase inhibitors have been well established and successfully developed in the last decades for cancer target therapies. However, intrinsic or acquired drug resistance is becoming the major barrier for their clinical application. With the development of immunotherapies, in particular the discovery of immune checkpoint inhibitors (ICIs), the combination of ICIs with other therapies have recently been extensively explored, among which combination of ICIs with kinase inhibitors achieves promising clinical outcome in a plethora of cancer types. Here we comprehensively summarize the potent roles of protein kinases in modulating immune checkpoints both in tumor and immune cells, and reshaping tumor immune microenvironments by evoking innate immune response and neoantigen generation or presentation. Moreover, the clinical trial and approval of combined administration of kinase inhibitors with ICIs are collected, highlighting the precise strategies to benefit cancer immune therapies.

Dissecting Tissue Compartment-Specific Protein Signatures in Primary and Metastatic Oropharyngeal Squamous Cell Carcinomas

Head and neck squamous cell carcinoma (HNSCC) often presents with locoregional or distant disease, despite multimodal therapeutic approaches, which include surgical resection, chemoradiotherapy, and more recently, immunotherapy for metastatic or recurrent HNSCC. Therapies often target the primary and nodal regional HNSCC sites, and their efficacy at controlling occult distant sites remains poor. While our understanding of the tumor microenvironment conducive to effective therapies is increasing, the biology underpinning locoregional sites remains unclear. Here, we applied targeted spatial proteomic approaches to primary and lymph node metastasis from an oropharyngeal SCC (OPSCC) cohort to understand the expression of proteins within tumors, and stromal compartments of the respective sites in samples of both matched and unmatched patients. In unmatched analyses of n = 43 primary and 11 nodal metastases, our data indicated that tumor cells in nodal metastases had higher levels of Ki-67, PARP, BAD, and cleaved caspase 9, suggesting a role for increased proliferation, DNA repair, and apoptosis within these metastatic cells. Conversely, in matched analyses (n = 7), pro-apoptotic markers BIM and BAD were enriched in the stroma of primary tumors. Univariate, overall survival (OS) analysis indicated CD25 in tumor regions of primary tumors to be associated with reduced survival (HR = 3.3, p = 0.003), while progesterone receptor (PR) was associated with an improved OS (HR = 0.33, p = 0.015). This study highlights the utility of spatial proteomics for delineating the tumor and stromal compartment composition, and utility toward understanding these properties in locoregional metastasis. These findings indicate unique biological properties of lymph node metastases that may elucidate further understanding of distant metastatic in OPSCC.

Identify the Prognostic and Immune Profile of VSIR in the Tumor Microenvironment: A Pan-Cancer Analysis

VSIR is a critical immunomodulatory receptor that inhibits T cell effector function and maintains peripheral tolerance. However, the mechanism by which VSIR participates in tumor immunity in the pan-cancer tumor microenvironment remains unclear. This study systematically explored the prognostic and immune profile of VSIR in the tumor microenvironment of 33 cancers. We compared the expression patterns and molecular features of VSIR in the normal and cancer samples both from the public databases and tumor chips. VSIR level was significantly related to patients’ prognosis and could be a promising predictor in many tumor types, such as GBM, KIRC, SKCM, READ, and PRAD. Elevated VSIR was closely correlated with infiltrated inflammatory cells, neoantigens expression, MSI, TMB, and classical immune checkpoints in the tumor microenvironment. Enrichment signaling pathways analysis indicated VSIR was involved in several immune-related pathways such as activation, proliferation, and migration of fibroblast, T cell, mast cell, macrophages, and foam cell. In addition, VSIR was found to widely express on cancer cells, fibroblasts, macrophages, and T cells in many tumor types based on the single-cell sequencing analysis and co-express with M2 macrophage markers CD68, CD163 based on the immunofluorescence staining. Finally, we predicted the sensitive drugs targeting VSIR and the immunotherapeutic value of VSIR. In sum, VSIR levels strongly correlated with the clinical outcome and tumor immunity in multiple cancer types. Therefore, therapeutic strategies targeting VSIR in the tumor microenvironment may be valuable tools for cancer immunotherapy.

Toll-like receptor agonist combinations augment mouse T-cell anti-tumor immunity via IL-12- and interferon ß-mediated suppression of immune checkpoint receptor expression

We previously found that activated CD8+ T-cells increase expression of PD-1, which can be attenuated in the presence of specific Toll-like receptor (TLR) agonists, mediated by IL-12 secreted by professional antigen-presenting cells. While these CD8+ T-cells had greater anti-tumor activity, T-cells stimulated by different TLR had different gene expression profiles. Consequently, we sought to determine whether combinations of TLR agonists might further affect the expression of T-cell checkpoint receptors and improve T-cell anti-tumor immunity. Activation of CD8+ T-cells in the presence of specific TLR ligands resulted in decreased expression of PD-1, LAG-3, and CD160, notably with combinations of TLR1/2, TLR3, and TLR9 agonists. Immunization of E.G7-OVA or TRAMP-C1 tumor-bearing mice with peptide or DNA vaccines, co-administered with combination of TLR3 and TLR9 agonists, showed greater suppression of tumor growth. The anti-tumor effect of TLR1/2 and/or TLR9, but not TLR3, was abrogated in IL-12KO mice. RNA sequencing of TLR-conditioned CD8+ T-cells revealed IL-12 pathway activation, and type 1 IFN pathway activation following TLR3 stimulation. Our results provide a mechanistic rationale for the choice of optimal combinations of TLR ligands to use as adjuvants to improve the efficacy of anti-tumor vaccines.

Next generation of immune checkpoint molecules in maternal-fetal immunity

Successful pregnancy is a unique situation requires the maternal immune system to recognize and tolerate a semi-identical fetus and allow normal invasion of trophoblast cells. Although efforts have been made, the deep mechanisms of the maternal-fetal crosstalk have not yet been fully deciphered. Immune checkpoint molecules (ICMs) are a group of negative modulators of the immune response that avoid immune damage. They have been extensively studied in the fields of oncology and transplantation, while the latest evidence suggests that they are closely associated with pregnancy outcomes via multiple inhibitory mechanisms. Although studies have mostly demonstrated the regulatory role of the well-known PD-1, CTLA-4 at the maternal-fetal interface, what is unique about the newly discovered multiple ICMs remains a mystery. Here, we review the latest knowledge on ICMs, focusing on the first generation of checkpoints (PD-1, CTLA-4) and the next generation (Tim-3, Tigit, Lag-3, VISTA) highlighting their immunoregulatory roles in maternal-fetal tolerance and decidual vascular remodeling, and their involvement in pathological pregnancies. The content covers three aspects: the characteristics they possess, the dynamic expression profile of their expression at the maternal-fetal interface, and their involvement in pathological pregnancy. In immunotherapy strategies for pregnancy complications, upregulation of immune checkpoints may play a role. Meanwhile, the impact on pregnancy outcomes when using ICMs in clinical cancer treatment during pregnancy is a topic worth exploring. These may serve as a guide for future basic research and clinical applications of maternal-fetal immunity.

Different clinical significance of novel B7 family checkpoints VISTA and HHLA2 in human lung adenocarcinoma

Background: VISTA and HHLA2 are two recently identified members of the B7 homologue family of immune-regulatory molecules. But the expression patterns and clinical significance of VISTA and HHLA2 in lung adenocarcinoma (LUAD) remain largely unknown. Methods: Immunohistochemistry was performed to examine the expression of VISTA, HHLA2, PD-L1 and CD8⁺ tumor-infiltrating lymphocytes in 74 cases of LUAD. The expression of VISTA, HHLA2, PD-L1, CD68 and CD8 proteins was detected by multiplex immunofluorescence staining in the LUAD tissues. Results: High expression of VISTA and HHLA2 was observed in LUAD compared with noncancerous tissues. High VISTA expression in immune cells predicted a high mortality rate and worse survival. Conclusion: VISTA and HHLA2 are potential immunotherapeutic targets that possess different prognostic significance in LUAD.

Landscape of Immunotherapy Options for Colorectal Cancer: Current Knowledge and Future Perspectives beyond Immune Checkpoint Blockade

Colorectal cancer is the third most prevalent malignancy in Western countries and a major cause of death despite recent improvements in screening programs and early detection methods. In the last decade, a growing effort has been put into better understanding how the immune system interacts with cancer cells. Even if treatments with immune checkpoint inhibitors (anti-PD1, anti-PD-L1, anti-CTLA4) were proven effective for several cancer types, the benefit for colorectal cancer patients is still limited. However, a subset of patients with deficient mismatch repair (dMMR)/microsatellite-instability-high (MSI-H) metastatic colorectal cancer has been observed to have a prolonged benefit to immune checkpoint inhibitors. As a result, pembrolizumab and nivolumab +/- ipilimumab recently obtained the Food and Drug Administration approval. This review aims to highlight the body of knowledge on immunotherapy in the colorectal cancer setting, discussing the potential mechanisms of resistance and future strategies to extend its use.

Targeting immune checkpoints in gynecologic cancer: updates & perspectives for pathologists

Checkpoint inhibitor-based immunotherapy is increasingly used in the treatment of gynecologic cancers, and most often targets the PD-1/PD-L1 axis. Pathologists should be familiar with the biomarkers required to determine candidacy for these treatments based on existing FDA approvals, including mismatch repair protein immunohistochemistry, microsatellite instability testing, tumor mutation burden testing, and PD-L1 immunohistochemistry. This review summarizes the rationale behind these treatments and their associated biomarkers and delivers guidance on how to utilize and readout these tests. It also introduces additional biomarkers which may provide information regarding immunotherapeutic vulnerability in the future such as neoantigen load; POLE mutation status; and immunohistochemical expression of immunosuppressive checkpoints like LAG-3, TIM-3, TIGIT, and VISTA; immune-activating checkpoints such as CD27, CD40, CD134, and CD137; enzymes such as IDO-1 and adenosine-related compounds; and MHC class I.

Immune Regulatory Processes of the Tumor Microenvironment under Malignant Conditions

The tumor microenvironment (TME) is a critical regulator of tumor growth, progression, and metastasis. Since immune cells represent a large fraction of the TME, they play a key role in mediating pro- and anti-tumor immune responses. Immune escape, which suppresses anti-tumor immunity, enables tumor cells to maintain their proliferation and growth. Numerous mechanisms, which have been intensively studied in recent years, are involved in this process and based on these findings, novel immunotherapies have been successfully developed. Here, we review the composition of the TME and the mechanisms by which immune evasive processes are regulated. In detail, we describe membrane-bound and soluble factors, their regulation, and their impact on immune cell activation in the TME. Furthermore, we give an overview of the tumor/antigen presentation and how it is influenced under malignant conditions. Finally, we summarize novel TME-targeting agents, which are already in clinical trials for different tumor entities.

Nature and Significance of Stromal Differentiation,, PD-L1, and VISTA in GIST

The role of stromal differentiation (SD), program death-ligand 1 (PD-L1), and v-domain Ig suppressor of T cell activation (VISTA) in gastrointestinal stromal tumor (GIST) is largely unknown. Looking forward, the assessment of SD and immune check point inhibition will become more ubiquitous in surgical pathology. Immature, myxoid stroma has been found to be a poor prognostic signature in many cancer subtypes (colon, breast, cervix, esophagus, stomach); although little is known regarding its significance in GIST. For immune check-point inhibition, studies have demonstrated expression to be associated with patient outcomes in numerous cancer subtypes. The present body of work aims to evaluate SD, PD-L1 and VISTA; both in terms of its nature and significance in a clinical setting. Here we found PD-L1 expression in immune cells (IC) and immature SD to be associated with worse cancer free survival, while positive VISTA expression was found to be associated with improved outcomes. High-grade, immature SD had the highest propensity for death/recurrence and was the only variable found to have prognostic significance on multivariate analysis. Our findings support the evaluation of SD, PD-L1 and VISTA in GIST, with clinical practice implications for pathologists. Ultimately, we hope our findings lead to improved prognostication, further optimization of therapeutics, and improved outcomes in a true clinical environment. For GIST, PD-L1 and VISTA could be both clinically relevant and targetable, while SD may be the answer to clinical heterogeneity.

Discovery of Novel Inhibitors From Medicinal Plants for V-Domain Ig Suppressor of T-Cell Activation

V-domain Ig suppressor of T cell activation (VISTA) is an immune checkpoint and is a type I transmembrane protein. VISTA is linked to immunotherapy resistance, and it is a potential immune therapeutic target, especially for triple-negative breast cancer. It expresses at a high concentration in regulatory T cells and myeloid-derived suppressor cells, and its functional blockade is found to delay tumor growth. A useful medicinal plant database for drug designing (MPD3), which is a collection of phytochemicals from diverse plant families, was employed in virtual screening against VISTA to prioritize natural inhibitors against VISTA. Three compounds, Paratocarpin K (PubChem ID: 14187087), 3-(1H-Indol-3-yl)-2-(trimethylazaniumyl)propanoate (PubChem ID: 3861164), and 2-[(5-Benzyl-4-ethyl-1,2,4-triazol-3-yl)sulfanylmethyl]-5-methyl-1,3,4-oxadiazole (PubChem ID: 6494266), having binding energies stronger than -6 kcal/mol were found to have two common hydrogen bond interactions with VISTA active site residues: Arg54 and Arg127. The dynamics of the compound-VISTA complexes were further explored to infer binding stability of the systems. Results revealed that the compound 14187087 and 6494266 systems are highly stable with an average RMSD of 1.31 Å. Further affirmation on the results was achieved by running MM-GBSA on the MD simulation trajectories, which re-ranked 14187087 as the top-binder with a net binding energy value of -33.33 kcal/mol. In conclusion, the present study successfully predicted natural compounds that have the potential to block the function of VISTA and therefore can be utilized further in experimental studies to validate their real anti-VISTA activity.

VISTA inhibitors in cancer immunotherapy: a short perspective on recent progresses

V-domain immunoglobulin (Ig) suppressor of T cell activation (VISTA) is a novel negative checkpoint regulator that mediates T cell proliferation and cytokine production. The VISTA signaling pathway blockade has been proved as a promising strategy for cancer immunotherapy. Recent VISTA sequence analysis and crystal structure investigations have revealed its independent and unique function as compared with B7 family members, such as PD-1. This review will discuss VISTA binding partners and compare the structural differences between VISTA and other B7 family members, focusing on VISTA functions in immune activation and maintaining T cell quiescence. Recent progress and the therapeutic potential of biomacromolecules, such as monoclonal antibodies (mAbs) and small molecules targeting VISTA, are also discussed. Among these, a first-in-class small-molecule antagonist, CA-170, is highlighted.

The Positive and Negative Immunoregulatory Role of B7 Family: Promising Novel Targets in Gastric Cancer Treatment

Gastric cancer (GC), with a heterogeneous nature, is the third leading cause of death worldwide. Over the past few decades, stable reductions in the incidence of GC have been observed. However, due to the poor response to common treatments and late diagnosis, this cancer is still considered one of the lethal cancers. Emerging methods such as immunotherapy with immune checkpoint inhibitors (ICIs) have transformed the landscape of treatment for GC patients. There are presently eleven known members of the B7 family as immune checkpoint molecules: B7-1 (CD80), B7-2 (CD86), B7-H1 (PD-L1, CD274), B7-DC (PDCD1LG2, PD-L2, CD273), B7-H2 (B7RP1, ICOS-L, CD275), B7-H3 (CD276), B7-H4 (B7x, B7S1, Vtcn1), B7-H5 (VISTA, Gi24, DD1α, Dies1 SISP1), B7-H6 (NCR3LG1), B7-H7 (HHLA2), and Ig-like domain-containing receptor 2 (ILDR2). Interaction of the B7 family of immune-regulatory ligands with the corresponding receptors resulted in the induction and inhibition of T cell responses by sending co-stimulatory and co-inhibitory signals, respectively. Manipulation of the signals provided by the B7 family has significant potential in the management of GC.

Superpixel image segmentation of VISTA expression in colorectal cancer and its relationship to the tumoral microenvironment

Colorectal cancer (CRC) is the third most common cause of cancer related death in the United States (Jasperson et al. in Gastroenterology 138:2044–2058, 10.1053/j.gastro.2010.01.054, 2010). Many studies have explored prognostic factors in CRC. Today, much focus has been placed on the tumor microenvironment, including different immune cells and the extracellular matrix (ECM). The present study aims to evaluate the role of V-domain immunoglobulin suppressor of T cell activation (VISTA). We utilized QuPath for whole slides image analysis, performing superpixel image segmentation (SIS) on a 226 patient-cohort. High VISTA expression correlated with better disease-free survival (DFS), high tumor infiltrative lymphocyte, microsatellite instability, BRAF mutational status as well as lower tumor stage. High VISTA expression was also associated with mature stromal differentiation (SD). When cohorts were separated based on SD and MMR, only patients with immature SD and microsatellite stability were found to correlate VISTA expression with DFS. Considering raised VISTA expression is associated with improved survival, TILs, mature SD, and MMR in CRC; careful, well-designed clinical trials should be pursued which incorporate the underlying tumoral microenvironment.

Immune functions as a ligand or a receptor, cancer prognosis potential, clinical implication of VISTA in cancer immunotherapy

Since cancer immunotherapy with immune checkpoint inhibitors of PD/PDL-1 and CTLA-4 limited efficacy to the patients due to resistance during the current decade, novel target is required for customized treatment due to tumor heterogeneity. V-domain Ig-containing suppressor of T cell activation (VISTA), a programmed death protein-1(PD-1) homolog expressed on T cells and on antigen presenting cells(APC), has emerged as a new target in several cancers. Though VISTA inhibitors including CA-170 are considered attractive in cancer immunotherapy to date, the information on VISTA as a potent biomarker of cancer prognosis and its combination therapy is still lacking to date. Thus, in this review, we discussed extracellular domain, ligands, expression, immune functions and clinical implications of VISTA and finally suggested conclusion and perspectives.

Clinical Research on the Mechanisms Underlying Immune Checkpoints and Tumor Metastasis

This study highlights aspects of the latest clinical research conducted on the relationship between immune checkpoints and tumor metastasis. The overview of each immune checkpoint is divided into the following three sections: 1) structure and expression; 2) immune mechanism related to tumor metastasis; and 3) clinical research related to tumor metastasis. This review expands on the immunological mechanisms of 17 immune checkpoints, including TIM-3, CD47, and OX-40L, that mediate tumor metastasis; evidence shows that most of these immune checkpoints are expressed on the surface of T cells, which mainly exert immunomodulatory effects. Additionally, we have summarized the roles of these immune checkpoints in the diagnosis and treatment of metastatic tumors, as these checkpoints are considered common predictors of metastasis in various cancers such as prostate cancer, non-Hodgkin lymphoma, and melanoma. Moreover, certain immune checkpoints can be used in synergy with PD-1 and CTLA-4, along with the implementation of combination therapies such as LIGHT-VTR and anti-PD-1 antibodies. Presently, most monoclonal antibodies generated against immune checkpoints are under investigation as part of ongoing preclinical or clinical trials conducted to evaluate their efficacy and safety to establish a better combination treatment strategy; however, no significant progress has been made regarding monoclonal antibody targeting of CD28, VISTA, or VTCN1. The application of immune checkpoint inhibitors in early stage tumors to prevent tumor metastasis warrants further evidence; the immune-related adverse events should be considered before combination therapy. This review aims to elucidate the mechanisms of immune checkpoint and the clinical progress on their use in metastatic tumors reported over the last 5 years, which may provide insights into the development of novel therapeutic strategies that will assist with the utilization of various immune checkpoint inhibitors.

New emerging targets in cancer immunotherapy: the role of VISTA

The immune surveillance system is complex and regulated by different actors. Programmed death protein-ligand 1 (PD-L1), the only approved biomarker in clinical practice, has proven to be imperfect in selecting patients to immune checkpoint inhibitors treatment. Therefore, new biomarkers, and new therapeutic targets, are needed to maximise the efficacy of immunotherapy. V-domain Ig Suppressor of T-cell Activation (VISTA) is a programmed death protein-1 (PD-1) homolog expressed on T cells and on antigen-presenting cells, which regulates processes of activation and repression of the immune system with not yet completely clarified mechanisms. Its blockage has demonstrated in vitro and in vivo antitumour activity. The clinical research of VISTA antagonists is ongoing. Particularly, CA-170, an orally delivered dual inhibitor of VISTA and PD-L1, has shown to have clinical efficacy in phase I and II clinical trials in different advanced solid tumour types. Further data are needed to define whether this drug class can become a new therapeutic option for patients with VISTA expressing cancers.

PD-1 and beyond to Activate T Cells in Cutaneous Squamous Cell Cancers: The Case for 4-1BB and VISTA Antibodies in Combination Therapy

Non-melanoma skin cancers (NMSC) have a higher incidence than all other cancers combined with cutaneous squamous cell carcinoma (cSCC), capable of metastasis, representing approximately 20% of NMSCs. Given the accessibility of the skin, surgery is frequently employed to treat localized disease, although certain localities, the delineation of clear margins, frequency and recurrence of tumors can make these cancers inoperable in a subset of patients. Other treatment modalities, including cryotherapy, are commonly used for individual lesions, with varying success. Immunotherapy, particularly with checkpoint antibodies, is increasingly a promising therapeutic approach in many cancers, offering the potential advantage of immune memory for protection against lesion recurrence. This review addresses a role for PD-1, 4-1BB and VISTA checkpoint antibodies as monotherapies, or in combination as a therapeutic treatment for both early and late-stage cSCC.

Detection of Immune Checkpoint Receptors - A Current Challenge in Clinical Flow Cytometry

Immunological therapy principles are increasingly determining modern medicine. They are used to treat diseases of the immune system, for tumors, but also for infections, neurological diseases, and many others. Most of these therapies base on antibodies, but small molecules, soluble receptors or cells and modified cells are also used. The development of immune checkpoint inhibitors is amazingly fast. T-cell directed antibody therapies against PD-1 or CTLA-4 are already firmly established in the clinic. Further targets are constantly being added and it is becoming increasingly clear that their expression is not only relevant on T cells. Furthermore, we do not yet have any experience with the long-term systemic effects of the treatment. Flow cytometry can be used for diagnosis, monitoring, and detection of side effects. In this review, we focus on checkpoint molecules as target molecules and functional markers of cells of the innate and acquired immune system. However, for most of the interesting and potentially relevant parameters, there are still no test kits suitable for routine use. Here we give an overview of the detection of checkpoint molecules on immune cells in the peripheral blood and show examples of a possible design of antibody panels.

Comparative Analysis and in vitro Experiments of Signatures and Prognostic Value of Immune Checkpoint Genes in Colorectal Cancer

Purpose

Immune checkpoints, as pivotal regulators of immune escape in cancer, can motivate the emergence of immune checkpoint inhibitors (ICIs). The aim of this study is to identify the expression of the immune checkpoint genes (ICGs) in colorectal cancer (CRC) and to relate their individual as well as combined expression to prognosis and therapeutic effectiveness in CRC.

Methods

RNA expression of 47 ICGs and clinical information of CRC patients were collected from two public databases to elucidate the expression levels and prognostic values of these ICGs in CRC. Then, the Shapiro–Wilk normality test was used to determine the normality of variables. Overall survival (OS) rates of each subset were found by Kaplan–Meier method, and the statistical significance was determined by the Log rank test (p < 0.05).

Results

The expression of 13 and 9 ICGs was significantly associated with CRC prognosis in The Cancer Genome Atlas (TCGA) and Gene Expression Omnibus (GEO) cohorts. A series of ICGs was found to be significantly associated with TMB, neoantigens and MMR in CRC indicating that the combination of immunotherapy treatment biomarkers and ICGs may achieve accurate prognostic stratification of CRC, and potentially identify CRC cases that might respond to checkpoint inhibitors (CPIs). The subsets of high or low PD1/PD-L1/IDO1 expression stratified by CD48 were accurately associated with prognosis in CRC. In addition, in vitro experiments confirmed that VTCN1(B7-H4)-KD increases anti-PD-L1-mediated NK cell cytotoxicity on CRC tumor cells.

Conclusion

Although the expression of a single immune-checkpoint molecule does not predict the efficacy of immunotherapy in CRC, our findings infer that subsets defined by ICGs are associated with prognosis and imply the possibility that VTCN1 and CD48 serve as new immunotherapeutic targets.

VISTA regulates microglia homeostasis and myelin phagocytosis, and is associated with MS lesion pathology

V-type immunoglobulin domain-containing suppressor of T-cell activation (VISTA) is a negative checkpoint regulator (NCR) that is involved in T-cell quiescence, inhibition of T-cell activation, and in myeloid cells regulates cytokine production, chemotaxis, phagocytosis, and tolerance induction. In the central nervous system (CNS), VISTA is expressed by microglia, the resident macrophage of the parenchyma, and expression is decreased during neuroinflammation; however, the function of VISTA in microglia is unknown. Here, we extensively analyzed VISTA expression in different MS lesion stages and characterized the function of VISTA in the CNS by deleting VISTA in microglia. VISTA is differentially expressed in distinct MS lesion stages. In mice, VISTA deletion in Cx3Cr1-expressing cells induced a more amoeboid microglia morphology, indicating an immune-activated phenotype. Expression of genes associated with cell cycle and immune-activation was increased in VISTA KO microglia. In response to LPS and during experimental autoimmune encephalomyelitis (EAE), VISTA KO and WT microglia shared similar transcriptional profiles and VISTA deletion did not affect EAE disease progression or microglia responses. VISTA KO in microglia in vitro decreased the uptake of myelin. This study demonstrates that VISTA is involved in microglia function, which likely affects healthy CNS homeostasis and neuroinflammation.

Immune Checkpoints, Inhibitors and Radionuclides in Prostate Cancer: Promising Combinatorial Therapy Approach

Emerging research demonstrates that co-inhibitory immune checkpoints (ICs) remain the most promising immunotherapy targets in various malignancies. Nonetheless, ICIs have offered insignificant clinical benefits in the treatment of advanced prostate cancer (PCa) especially when they are used as monotherapies. Current existing PCa treatment initially offers an improved clinical outcome and overall survival (OS), however, after a while the treatment becomes resistant leading to aggressive and uncontrolled disease associated with increased mortality and morbidity. Concurrent combination of the ICIs with radionuclides therapy that has rapidly emerged as safe and effective targeted approach for treating PCa patients may shift the paradigm of PCa treatment. Here, we provide an overview of the contextual contribution of old and new emerging inhibitory ICs in PCa, preclinical and clinical studies supporting the use of these ICs in treating PCa patients. Furthermore, we will also describe the potential of using a combinatory approach of ICIs and radionuclides therapy in treating PCa patients to enhance efficacy, durable cancer control and OS. The inhibitory ICs considered in this review are cytotoxic T-lymphocyte antigen 4 (CTLA4), programmed cell death 1 (PD1), V-domain immunoglobulin suppressor of T cell activation (VISTA), indoleamine 2,3-dioxygenase (IDO), T cell Immunoglobulin Domain and Mucin Domain 3 (TIM-3), lymphocyte-activation gene 3 (LAG-3), T cell immunoreceptor with Ig and ITIM domains (TIGIT), B7 homolog 3 (B7-H3) and B7-H4.

Combined Assessment of Immune Checkpoint Regulator VISTA on Tumor-Associated Immune Cells and Platelet-to-Lymphocyte Ratio Identifies Advanced Germ Cell Tumors with Higher Risk of Unfavorable Outcomes

Simple Summary

Testicular germ cell tumors (GCTs) are the most common malignancies in young males. The current treatment regimens are usually highly effective and curative. Nevertheless, a portion of patients presents with recurrence or succumbs due to the disease. There is an undoubtful necessity to investigate new prognostic markers to stratify the risk of such events. The current study aimed to evaluate the prognostic significance of markers of the tumor microenvironment and systemic inflammation markers in GCTs. We found that low expression of immune checkpoint proteins VISTA (V-domain Ig suppressor of T cell activation) and PD-L1 (programmed death-ligand 1) on tumor-associated immune cells and elevated inflammatory marker platelet-to-lymphocyte ratio are associated with a higher risk of events in testicular GCTs. It indicates a role of both local anti-tumor immune response and systemic inflammation in these tumors.

Abstract

In the current study, we aimed to investigate whether expression of immune checkpoint proteins (V-domain Ig suppressor of T cell activation (VISTA) and programmed death-ligand 1 (PD-L1)) and markers of systemic inflammation could predict progression/relapse and death in the cohort of 180 patients with testicular germ-cell tumors (GCTs). Expression of PD-L1 and VISTA was assessed by immunohistochemistry utilizing tissue microarrays. To estimate systemic inflammation neutrophil-to-lymphocyte ratio (NLR), lymphocyte-to-monocyte ratio (LMR), and platelet-to-lymphocyte ratio (PLR) were calculated. We found high PD-L1 and VISTA expression on tumor-associated immune cells (TAICs) in 89 (49.44%) and 63 (37.22%) of GCTs, respectively, whereas tumor cells besides trophoblastic elements were almost uniformly negative. High PD-L1 was associated with seminomatous histology and lower stage. Relapses in stage I patients occurred predominantly in cases with low numbers of PD-L1 and VISTA-expressing TAICs. In stage II/III disease, the combination of low VISTA-expressing TAICs and high PLR was identified as predictor of shorter event-free survival (HR 4.10; 1.48–11.36, p = 0.006) and overall survival (HR 15.56, 95% CI 1.78–135.51, p = 0.001) independently of tumor histology and location of metastases. We demonstrated that the assessment of immune checkpoint proteins on TAICs may serve as a valuable prognostic factor in patients with high-risk testicular GCTs. Further study is warranted to explore the predictive utility of these biomarkers in GCTs.

Rethinking peripheral T cell tolerance: checkpoints across a T cell's journey

Following their exit from the thymus, T cells are endowed with potent effector functions but must spare host tissue from harm. The fate of these cells is dictated by a series of checkpoints that regulate the quality and magnitude of T cell-mediated immunity, known as tolerance checkpoints. In this Perspective, we discuss the mediators and networks that control the six main peripheral tolerance checkpoints throughout the life of a T cell: quiescence, ignorance, anergy, exhaustion, senescence and death. At the naive T cell stage, two intrinsic checkpoints that actively maintain tolerance are quiescence and ignorance. In the presence of co-stimulation-deficient T cell activation, anergy is a dominant hallmark that mandates T cell unresponsiveness. When T cells are successfully stimulated and reach the effector stage, exhaustion and senescence can limit excessive inflammation and prevent immunopathology. At every stage of the T cell's journey, cell death exists as a checkpoint to limit clonal expansion and to terminate unrestrained responses. Here, we compare and contrast the T cell tolerance checkpoints and discuss their specific roles, with the aim of providing an integrated view of T cell peripheral tolerance and fate regulation.

VISTA: A Target to Manage the Innate Cytokine Storm

In recent years, the success of immunotherapy targeting immunoregulatory receptors (immune checkpoints) in cancer have generated enthusiastic support to target these receptors in a wide range of other immune related diseases. While the overwhelming focus has been on blockade of these inhibitory pathways to augment immunity, agonistic triggering via these receptors offers the promise of dampening pathogenic inflammatory responses. V-domain Ig suppressor of T cell activation (VISTA) has emerged as an immunoregulatory receptor with constitutive expression on both the T cell and myeloid compartments, and whose agonistic targeting has proven a unique avenue relative to other checkpoint pathways to suppress pathologies mediated by the innate arm of the immune system. VISTA agonistic targeting profoundly changes the phenotype of human monocytes towards an anti-inflammatory cell state, as highlighted by striking suppression of the canonical markers CD14 and Fcγr3a (CD16), and the almost complete suppression of both the interferon I (IFN-I) and antigen presentation pathways. The insights from these very recent studies highlight the impact of VISTA agonistic targeting of myeloid cells, and its potential therapeutic implications in the settings of hyperinflammatory responses such as cytokine storms, driven by dysregulated immune responses to viral infections (with a focus on COVID-19) and autoimmune diseases. Collectively, these findings suggest that the VISTA pathway plays a conserved, non-redundant role in myeloid cell function.

Immunobiology and immunotherapy of HCC: spotlight on innate and innate-like immune cells

Immune-based therapies such as immune checkpoint inhibitors have revolutionized the systemic treatment of various cancer types. The therapeutic application of monoclonal antibodies targeting inhibitory pathways such as programmed cell death-1(PD-1)/programmed cell death ligand 1 (PD-L1) and CTLA-4 to cells of the adaptive immune system has recently been shown to generate meaningful improvement in the clinical outcome of hepatocellular carcinoma (HCC). Nevertheless, current immunotherapeutic approaches induce durable responses in only a subset of HCC patients. Since immunologic mechanisms such as chronic inflammation due to chronic viral hepatitis or alcoholic and nonalcoholic fatty liver disease play a crucial role in the initiation, development, and progression of HCC, it is important to understand the underlying mechanisms shaping the unique tumor microenvironment of liver cancer. The liver is an immunologic organ with large populations of innate and innate-like immune cells and is exposed to bacterial, viral, and fungal antigens through the gut-liver axis. Here, we summarize and highlight the role of these cells in liver cancer and propose strategies to therapeutically target them. We also discuss current immunotherapeutic strategies in HCC and outline recent advances in our understanding of how the therapeutic potential of these agents might be enhanced.

Emerging Targets of Immunotherapy in Gynecologic Cancer

Although programmed cell death protein 1/programmed death-ligand 1 (PD-1/PD-L1) and cytotoxic T lymphocyte antigen-4 (CTLA-4) have been successfully applied in the treatment of tumors, their efficiency is still not high enough. New immune targets need to be identified in order to seek alternative treatment strategies for patients with refractory tumors. Immune targets can be divided into stimulating and inhibiting molecules according to their function after receptor-ligand binding. We herein present a compendious summary of emerging immune targets in gynecologic tumors. These targets included coinhibitory molecules, such as T cell immunoglobulin-3 (TIM-3), T cell immunoglobulin and ITIM domain (TIGIT), lymphocyte activation gene-3 (LAG-3), V-type immunoglobulin domain-containing suppressor of T cell activation (VISTA), and B7-H3 and B7-H4, and co-stimulatory molecules, such as CD27, OX40, 4-1BB, CD40, glucocorticoid-induced tumor necrosis factor receptor (GITR) and inducible co-stimulator (ICOS). In this review, the characteristics and preclinical/clinical progress of gynecological malignancies are briefly discussed. However, the potential mechanisms and interactions of immune targets need to be elucidated in further studies.

Tumor Immune Microenvironments (TIMEs): Responsive Nanoplatforms for Antitumor Immunotherapy

Interest in cancer immunotherapy has rapidly risen since it offers many advantages over traditional approaches, such as high efficiency and prevention of metastasis. Efforts have primarily focused on two major strategies for regulating the body's antitumor immune response mechanisms: “enhanced immunotherapy” that aims to amplify the immune activation, and “normalized immunotherapy” that corrects the defective immune mechanism in the tumor immune microenvironments (TIMEs), which returns to the normal immune trajectory. However, due to the complexity and heterogeneity of the TIMEs, and lack of visualization research on the immunotherapy process, cancer immunotherapy has not been widely used in clinical setting. Recently, through the design and modification of nanomaterials, intelligent TIME-responsive nanoplatforms were developed from which encouraging results in many aspects of immunotherapy have been achieved. In this mini review, the status of designed nanomaterials for nanoplatform-based immune regulation of TIMEs has been emphasized, particularly with respect to the aforementioned approaches. It is envisaged that future prospects will focus on a combination of multiple immunotherapies for more efficient cancer inhibition and elimination.

VISTA Re-programs Macrophage Biology Through the Combined Regulation of Tolerance and Anti-inflammatory Pathways

We present the novel finding that V-domain Ig suppressor of T cell activation (VISTA) negatively regulates innate inflammation through the transcriptional and epigenetic re-programming of macrophages. Representative of VISTA re-programming is the ability of VISTA agonistic antibodies to augment LPS tolerance and reduce septic shock lethality in mice. This anti-inflammatory effect of anti-VISTA was mimicked in vitro demonstrating that anti-VISTA treatment caused a significant reduction in LPS-induced IL-12p40, IL-6, CXCL2, and TNF; all hallmark pro-inflammatory mediators of endotoxin shock. Even under conditions that typically "break" LPS tolerance, VISTA agonists sustained a macrophage anti-inflammatory profile. Analysis of the proteomic and transcriptional changes imposed by anti-VISTA show that macrophage re-programming was mediated by a composite profile of mediators involved in both macrophage tolerance induction (IRG1, miR221, A20, IL-10) as well as transcription factors central to driving an anti-inflammatory profile (e.g., IRF5, IRF8, NFKB1). These findings underscore a novel and new activity of VISTA as a negative checkpoint regulator that induces both tolerance and anti-inflammatory programs in macrophages and controls the magnitude of innate inflammation in vivo.

Novel strategies in immune checkpoint inhibitor drug development: How far are we from the paradigm shift?

The development of immune checkpoint inhibitors (ICI) represents a major milestone in immune-oncology. Over the years these agents have demonstrated efficacy in an increasing array of malignancies. Despite this success however, significant challenges remain. Novel approaches to both drug development and trial design are required to incorporate the unique pharmacokinetic and pharmacodynamic properties of ICIs. Further, it has also been established that the benefit of ICIs is limited to only a subset of patients. The molecular interactions between native immune cells and tumorigenesis and progression represent an active area of biomarker research, and elucidating the mechanisms of response and resistance is crucial to develop rational trial designs for the next wave of immune-oncology (IO) clinical trials, particularly in patients with primary and/or acquired resistance. Efforts are now being made to integrate both biological and clinical information using novel multi-omic approaches which are now being developed to further elucidate the molecular signatures associated with IO treatment response and resistance and enable rational drug development and trial design processes. As such, precision IO and the ability to deliver patient-specific choices for ICI monotherapies or combination therapies has become an increasingly tangible goal. We herein describe the current landscape in ICI drug development and discuss the challenges and future directions in this exciting and evolving era in immune-oncology.

Exploring the VISTA of microglia: immune checkpoints in CNS inflammation

Negative checkpoint regulators (NCR) are intensely pursued as targets to modulate the immune response in cancer and autoimmunity. A large variety of NCR is expressed by central nervous system (CNS)-resident cell types and is associated with CNS homeostasis, interactions with peripheral immunity and CNS inflammation and disease. Immunotherapy blocking NCR affects the CNS as patients can develop neurological issues including encephalitis and multiple sclerosis (MS). How these treatments affect the CNS is incompletely understood, since expression and function of NCR in the CNS are only beginning to be unravelled. V-type immunoglobulin-like suppressor of T cell activation (VISTA) is an NCR that is expressed primarily in the haematopoietic system by myeloid and T cells. VISTA regulates T cell quiescence and activation and has a variety of functions in myeloid cells including efferocytosis, cytokine response and chemotaxis. In the CNS, VISTA is predominantly expressed by microglia and macrophages of the CNS. In this review, we summarize the role of NCR in the CNS during health and disease. We highlight expression of VISTA across cell types and CNS diseases and discuss the function of VISTA in microglia and during CNS ageing, inflammation and neurodegeneration. Understanding the role of VISTA and other NCR in the CNS is important considering the adverse effects of immunotherapy on the CNS, and in view of their therapeutic potential in CNS disease.

B7-H6 as an efficient target for T cell-induced cytotoxicity in haematologic malignant cells

T cells play crucial roles in the antitumour immune response. However, their dysfunction leads to inefficient tumour eradication. New members of the B7 family have moved to the fore of cancer research because of their involvement in T cell-mediated immune escape and tumorigenesis. Recently, bispecific antibodies (Bi-Abs) have become attractive because of their ability to activate T cells to target tumours. In this study, we examined the expression of new B7 family members B7-H4, B7-H5, B7-H6, and B7-H7 in human haematological tumour cells. Furthermore, we explored whether B7-H6 is an efficient target for T cell-induced cytotoxicity in haematologic malignant cells. We determined the capability of T cells armed with the bispecific antibody anti-CD3 × anti-B7-H6 (B7-H6Bi-Ab) to target haematological tumours in K562, Thp-1, Daudi, Jurkat, and U266 cells. Compared with their T cell counterparts, B7-H6Bi-Ab-armed T cells demonstrated significant cytotoxicity induction in B7-H6⁺ haematological tumour cells, according to quantitative luciferase and lactate dehydrogenase assays, and their activity was accompanied by increased levels of the secreted killing mediators granzyme B and perforin. Moreover, B7-H6Bi-Ab-armed T cells produced more T cell-derived cytokines: TNF-α, IFN-γ, and IL-2. In addition, compared to the control T cells, a higher level of the activation marker CD69 was detected on the B7-H6Bi-Ab-armed T cells. Taken together, these data suggest that the antitumour effect of B7-H6Bi-Ab-armed T cells may be a promising immunotherapy for use in future haematologic treatments.

VISTA: an immune regulatory protein checking tumor and immune cells in cancer immunotherapy

VISTA (V-domain immunoglobulin suppressor of T cell activation) is a well-established immune regulatory receptor. However, pre-clinical investigations indicated more complicated influences of VISTA on cancer immunity than previously recognized. Here, we review the current knowledge on the therapeutic phenotypes and molecular mechanisms that underlie the contradictory roles of VISTA in checking anti-cancer immune responses. Furthermore, we highlight the potential indeterminacy of VISTA-targeted strategies in cancer immunotherapy, with in silico analyses. In fact, VISTA functions like a homeostatic regulator that actively normalizes immune responses. Thus, the regulatory role of VISTA in anti-cancer immunity remains to be fully elucidated.

The Role of B7 Family Molecules in Maternal-Fetal Immunity

Pregnancy is a complex but well-arranged process, and a healthy fetus requires immune privilege and surveillance in the presence of paternally derived antigens. Maternal and fetal cells interact at the maternal–fetal interface. The upregulation and downregulation of maternal immunity executed by the leukocyte population predominantly depend on the activity of decidual natural killer cells and trophoblasts and are further modulated by a series of duplex signals. The B7 family, which consists of B7-1, B7-2, B7-H1, B7-DC, B7-H2, B7-H3, B7-H4, B7-H5, BTNL2, B7-H6, and B7-H7, is one of the most characterized and widely distributed signaling molecule superfamilies and conducts both stimulatory and inhibitory signals through separate interactions. In particular, the roles of B7-1, B7-2, B7-H1, and their corresponding receptors in the progression of normal pregnancy and some pregnancy complications have been extensively studied. Together with the TCR–MHC complex, B7 and its receptors play a critical role in cell proliferation and cytokine secretion. Depending on this ligand–receptor crosstalk, the balance between the tolerance and rejection of the fetus is perfectly maintained. This review aims to provide an overview of the current knowledge of the B7 family and its functions in regulating maternal–fetal immunity through individual interactions.

VISTA: Coming of age as a multi-lineage immune checkpoint

The immune response is governed by a highly complex set of interactions among cells and mediators. T cells may be rendered dysfunctional by the presence of high levels of antigen in the absence of co-stimulation while myeloid cells may be programmed towards an immunosuppressive state that promotes cancer growth and metastasis while deterring tumor immunity. In addition, inhibitory programs driven by immune checkpoint regulators dampen anti-tumor immunity. The ideal cancer immunotherapy treatment will improve both cross-priming in the tumor microenvironment and relieve suppression by the inhibitory checkpoints. Recently, blockade of programmed cell death 1 (PD-1) and cytotoxic T lymphocyte antigen 4 (CTLA-4) has elicited impressive results, but not in all patients, so additional targets are under investigation. V-set immunoglobulin domain suppressor of T cell activation (VISTA) is a novel immunoregulatory receptor that is broadly expressed on cells of the myeloid and lymphoid lineages, and is frequently implicated as a poor prognostic indicator in multiple cancers. Importantly, antibody targeting of VISTA uniquely engages both innate and adaptive immunity. This, combined with the expression of VISTA and its non-redundant activities compared to other immune checkpoint regulators, qualifies VISTA to be a promising target for improving cancer immunotherapy.

VISTA is a checkpoint regulator for naïve T cell quiescence and peripheral tolerance

Negative checkpoint regulators (NCRs) temper the T cell immune response to self-antigens and limit the development of autoimmunity. Unlike all other NCRs that are expressed on activated T lymphocytes, V-type immunoglobulin domain-containing suppressor of T cell activation (VISTA) is expressed on naïve T cells. We report an unexpected heterogeneity within the naïve T cell compartment in mice, where loss of VISTA disrupted the major quiescent naïve T cell subset and enhanced self-reactivity. Agonistic VISTA engagement increased T cell tolerance by promoting antigen-induced peripheral T cell deletion. Although a critical player in naïve T cell homeostasis, the ability of VISTA to restrain naïve T cell responses was lost under inflammatory conditions. VISTA is therefore a distinctive NCR of naïve T cells that is critical for steady-state maintenance of quiescence and peripheral tolerance.

Immunologic alterations in the pancreatic cancer microenvironment of patients treated with neoadjuvant chemotherapy and radiotherapy

Pancreatic ductal adenocarcinoma (PDAC) has dismal 5-year survival (<9%). We hypothesize that exposure of tumors to conventional therapies may preferentially modulate immune biomarkers in the tumor microenvironment in PDAC. PDAC patients who underwent upfront surgical resection or who received neoadjuvant FOLFIRINOX with or without neoadjuvant radiotherapy followed by surgical resection were selected for study. Total expression of immunologically relevant transcripts and spatially resolved expression of immunologically relevant proteins was quantitated using multiplexed methods (NanoString nCounter and GeoMX platforms). This analysis identified numerous differentially expressed transcripts associated with the type of neoadjuvant therapy received. Moreover, we identified significant alterations in the expression and/or spatial distribution of immunologically relevant proteins in different regions (tumor cell rich, immune cell rich, stromal cell rich) of the tumor microenvironment. These data provide insight into the immunological effects of clinically relevant neoadjuvant therapy for resectable/borderline-resectable PDAC by describing significant differences in the expression of key immunologic biomarkers within the PDAC microenvironment that were associated with the type of treatment patients received prior to surgical resection. This represents a comprehensive analysis of numerous biomarkers conducted on the PDAC microenvironment. This work may guide strategic new combination therapies for pancreatic cancer.