An immunogenic WT1-derived peptide that induces T cell response in the context of HLA-A*02:01 and HLA-A*24:02 molecules

REGAL: galinpepimut-S vs. best available therapy as maintenance therapy for acute myeloid leukemia in second remission

Patients with relapsed or refractory (r/r) acute myeloid leukemia (AML) have very poor long-term outcomes. Allogeneic stem cell transplantation (allo-SCT) can potentially cure some of these patients who are able to achieve a second or greater remission with salvage chemotherapy. Unfortunately, several barriers exist to transplantation and not all patients with r/r AML are able to proceed to allo-SCT. Therefore, novel therapies to decrease the risk of relapse in these patients are urgently needed. Wilms tumor 1 (WT1) protein has emerged as an encouraging vaccine target in AML due to its overexpression in leukemic blast cells and near absence in normal hematopoietic cells. Maintenance therapy with galinpepimut-S, a multivalent heteroclitic WT1 peptide vaccine, holds promise in early phase trials, in patients with AML by inducing a strong innate immune response against the WT1 antigen, leading to the design of this international, open-label, randomized clinical trial, named REGAL. Clinical trial registration: https://clinicaltrials.gov/study/NCT04229979. The clinical trial identifier is NCT04229979.

Generation and evaluation of cancer binding capacity of HLA-A2-WT1 complex-targeting antibody

Wilms' tumor (WT1), a transcription factor highly expressed in various leukemias and solid tumors, is a highly specific intracellular tumor antigen, requiring presentation through complexation with HLA-restricted peptides.. WT1-derived epitopes are able to assemble with MHC-I and thereby be recognized by T cell receptors (TCR). Identification of new targetable epitopes derived from WT1 on solid tumors is a challenge, but meaningful for the development of therapeutics that could in this way target intracellular oncogenic proteins. In this study, we developed and comprehensively describe methods to validate the formation of the complex of WT1126-134 and HLA-A2. Subsequently, we developed an antibody fragment able to recognize the extracellular complex on the surface of cancer cells. The single chain variable fragment (scFv) of an established TCR-mimic antibody, specifically recognizing the WT1-derived peptide presented by the HLA-A2 complex, was expressed, purified, and functionally validated using a T2 cell antigen presentation model. Furthermore, we evaluated the potential of the WT1-derived peptide as a targetable extracellular antigen in multiple solid tumor cell lines. Our study describes methodology for the evaluation of WT1-derived peptides as tumor-specific antigen on solid tumors, and may facilitate the selection of potential candidates for future immunotherapy targeting WT1 epitopes.

Estrogen Receptor Mutations as Novel Targets for Immunotherapy in Metastatic Estrogen Receptor-positive Breast Cancer

Estrogen receptor-positive (ER+) breast cancer is not considered immunogenic and, to date, has been proven resistant to immunotherapy. Endocrine therapy remains the cornerstone of treatment for ER+ breast cancers. However, constitutively activating mutations in the estrogen receptor alpha (ESR1) gene can emerge during treatment, rendering tumors resistant to endocrine therapy. Although these mutations represent a pathway of resistance, they also represent a potential source of neoepitopes that can be targeted by immunotherapy. In this study, we investigated ESR1 mutations as novel targets for breast cancer immunotherapy. Using machine learning algorithms, we identified ESR1-derived peptides predicted to form stable complexes with HLA-A*0201. We then validated the binding affinity and stability of the top predicted peptides through in vitro binding and dissociation assays and showed that these peptides bind HLA-A*0201 with high affinity and stability. Using tetramer assays, we confirmed the presence and expansion potential of antigen-specific CTLs from healthy female donors. Finally, using in vitro cytotoxicity assays, we showed the lysis of peptide-pulsed targets and breast cancer cells expressing common ESR1 mutations by expanded antigen-specific CTLs. Ultimately, we identified five peptides derived from the three most common ESR1 mutations (D538G, Y537S, and E380Q) and their associated wild-type peptides, which were the most immunogenic. Overall, these data confirm the immunogenicity of epitopes derived from ESR1 and highlight the potential of these peptides to be targeted by novel immunotherapy strategies.

SIGNIFICANCE

Estrogen receptor (ESR1) mutations have emerged as a key factor in endocrine therapy resistance. We identified and validated five novel, immunogenic ESR1-derived peptides that could be targeted through vaccine-based immunotherapy.

The good and the bad of T cell cross-reactivity: challenges and opportunities for novel therapeutics in autoimmunity and cancer

T cells are main actors of the immune system with an essential role in protection against pathogens and cancer. The molecular key event involved in this absolutely central task is the interaction of membrane-bound specific T cell receptors with peptide-MHC complexes which initiates T cell priming, activation and recall, and thus controls a range of downstream functions. While textbooks teach us that the repertoire of mature T cells is highly diverse, it is clear that this diversity cannot possibly cover all potential foreign peptides that might be encountered during life. TCR cross-reactivity, i.e. the ability of a single TCR to recognise different peptides, offers the best solution to this biological challenge. Reports have shown that indeed, TCR cross-reactivity is surprisingly high. Hence, the T cell dilemma is the following: be as specific as possible to target foreign danger and spare self, while being able to react to a large spectrum of body-threatening situations. This has major consequences for both autoimmune diseases and cancer, and significant implications for the development of T cell-based therapies. In this review, we will present essential experimental evidence of T cell cross-reactivity, implications for two opposite immune conditions, i.e. autoimmunity vs cancer, and how this can be differently exploited for immunotherapy approaches. Finally, we will discuss the tools available for predicting cross-reactivity and how improvements in this field might boost translational approaches.

MHC-Optimized Peptide Scaffold for Improved Antigen Presentation and Anti-Tumor Response

Tumor Associated Antigens (TAAs) may suffer from an immunological tolerance due to expression on normal cells. In order to potentiate their immunogenicity, heteroclitic peptides (htcPep) were designed according to prediction algorithms. In particular, specific modifications were introduced in peptide residues facing to TCR. Moreover, a MHC-optimized scaffold was designed for improved antigen presentation to TCR by H-2Db allele. The efficacy of such htcPep was assessed in C57BL/6 mice injected with syngeneic melanoma B16F10 or lung TC1 tumor cell lines, in combination with metronomic chemotherapy and immune checkpoint inhibitors. The immunogenicity of htcPep was significantly stronger than the corresponding wt peptide and the modification involving both MHC and TCR binding residues scored the strongest. In particular, the H-2Db-specific scaffold significantly potentiated the peptides' immunogenicity and control of tumor growth was comparable to wt peptide in a therapeutic setting. Overall, we demonstrated that modified TAAs show higher immunogenicity compared to wt peptide. In particular, the MHC-optimized scaffold can present different antigen sequences to TCR, retaining the conformational characteristics of the corresponding wt. Cross-reacting CD8+ T cells are elicited and efficiently kill tumor cells presenting the wild-type antigen. This novel approach can be of high clinical relevance in cancer vaccine development.

Trial Watch: Adoptive TCR-Engineered T-Cell Immunotherapy for Acute Myeloid Leukemia

Simple Summary

Acute myeloid leukemia (AML) is a type of blood cancer with an extremely grim prognosis. This is due to the fact that the majority of patients will relapse after frontline treatment. Overall survival of relapsed AML is very low, and treatment options are few. T lymphocytes harnessed with antitumor T-cell receptors (TCRs) can produce objective clinical responses in certain cancers, such as melanoma, but have not entered the main road for AML. In this review, we describe the current status of the field of TCR-T-cell therapies for AML.

Abstract

Despite the advent of novel therapies, acute myeloid leukemia (AML) remains associated with a grim prognosis. This is exemplified by 5-year overall survival rates not exceeding 30%. Even with frontline high-intensity chemotherapy regimens and allogeneic hematopoietic stem cell transplantation, the majority of patients with AML will relapse. For these patients, treatment options are few, and novel therapies are urgently needed. Adoptive T-cell therapies represent an attractive therapeutic avenue due to the intrinsic ability of T lymphocytes to recognize tumor cells with high specificity and efficiency. In particular, T-cell therapies focused on introducing T-cell receptors (TCRs) against tumor antigens have achieved objective clinical responses in solid tumors such as synovial sarcoma and melanoma. However, contrary to chimeric antigen receptor (CAR)-T cells with groundbreaking results in B-cell malignancies, the use of TCR-T cells for hematological malignancies is still in its infancy. In this review, we provide an overview of the status and clinical advances in adoptive TCR-T-cell therapy for the treatment of AML.

Immunopeptidomics-Guided Warehouse Design for Peptide-Based Immunotherapy in Chronic Lymphocytic Leukemia

Antigen-specific immunotherapies, in particular peptide vaccines, depend on the recognition of naturally presented antigens derived from mutated and unmutated gene products on human leukocyte antigens, and represent a promising low-side-effect concept for cancer treatment. So far, the broad application of peptide vaccines in cancer patients is hampered by challenges of time- and cost-intensive personalized vaccine design, and the lack of neoepitopes from tumor-specific mutations, especially in low-mutational burden malignancies. In this study, we developed an immunopeptidome-guided workflow for the design of tumor-associated off-the-shelf peptide warehouses for broadly applicable personalized therapeutics. Comparative mass spectrometry-based immunopeptidome analyses of primary chronic lymphocytic leukemia (CLL) samples, as representative example of low-mutational burden tumor entities, and a dataset of benign tissue samples enabled the identification of high-frequent non-mutated CLL-associated antigens. These antigens were further shown to be recognized by pre-existing and de novo induced T cells in CLL patients and healthy volunteers, and were evaluated as pre-manufactured warehouse for the construction of personalized multi-peptide vaccines in a first clinical trial for CLL (NCT04688385). This workflow for the design of peptide warehouses is easily transferable to other tumor entities and can provide the foundation for the development of broad personalized T cell-based immunotherapy approaches.

A Novel HAGE/WT1-ImmunoBody® Vaccine Combination Enhances Anti-Tumour Responses When Compared to Either Vaccine Alone

Many cancers, including myeloid leukaemia express the cancer testis antigen (CTA) DDX43 (HAGE) and/or the oncogene Wilms’ tumour (WT1). Here we demonstrate that HAGE/WT1-ImmunoBody^® vaccines derived T-cells can kill ex-vivo human CML cell lines expressing these antigens and significantly delay B16/HHDII⁺/DR1⁺/HAGE⁺/WT1⁺ tumour growth in the HHDII/DR1 mice and prolonged mouse survival in the prophylactic setting in comparison to non-immunised control mice. We show that immunisation of HHDII/DR1 mice with HAGE- and WT1-ImmunoBody^® DNA vaccines in a prime-boost regime in two different flanks induce significant IFN-γ release by splenocytes from treated mice, and a significant level of cytotoxicity against tumour targets expressing HAGE/WT1 in vitro. More importantly, the combined HAGE/WT1 ImmunoBody^® vaccine significantly delayed tumour growth in the B16/HHDII⁺/DR1⁺/HAGE⁺/WT1⁺ tumour model and prolonged mouse survival in the prophylactic setting in comparison to non-immunised control mice. Overall, this work demonstrates that combining both HAGE- and WT1-ImmunoBody^® into a single vaccine is better than either vaccine alone. This combination vaccine could be given to patients whose cancer expresses HAGE and WT1 in parallel with existing therapies in order to decrease the chance of disease progression and relapse.

Emerging self-assembling peptide nanomaterial for anti-cancer therapy

Recently it is mainly focused on anti-tumor comprehensive treatments like finding target tumor cells or activating immune cells to inhibit tumor recurrence and metastasis. At present, chemotherapy and molecular-targeted drugs can inhibit tumor cell growth to a certain extent. However, multi-drug resistance and immune escape often make it difficult for new drugs to achieve expected effects. Peptide hydrogel nanoparticles is a new type of biological material with functional peptide chains as the core and self-assembling peptide (SAP) as the framework. It has a variety of significant biological functions, including effective local inflammation suppression and non-drug-resistant cell killing. Besides, it can induce immune activation more persistently in an adjuvant independent manner when compared with simple peptides. Thus, SAP nanomaterial has great potential in regulating cell physiological functions, drug delivery and sensitization, vaccine design and immunotherapy. Not only that, it is also a potential way to focus on some specific proteins and cells through peptides, which has already been examined in previous research. A full understanding of the function and application of SAP nanoparticles can provide a simple and practical strategy for the development of anti-tumor drugs and vaccine design, which contributes to the historical transition of peptide nanohydrogels from bench to bedside and brings as much survival benefits as possible to cancer patients.

Sensitive and Quantitative Detection of MHC-I Displayed Neoepitopes Using a Semiautomated Workflow and TOMAHAQ Mass Spectrometry

Advances in several key technologies, including MHC peptidomics, have helped fuel our understanding of basic immune regulatory mechanisms and the identification of T cell receptor targets for the development of immunotherapeutics. Isolating and accurately quantifying MHC-bound peptides from cells and tissues enables characterization of dynamic changes in the ligandome due to cellular perturbations. However, the current multistep analytical process is challenging, and improvements in throughput and reproducibility would enable rapid characterization of multiple conditions in parallel. Here, we describe a robust and quantitative method whereby peptides derived from MHC-I complexes from a variety of cell lines, including challenging adherent lines such as MC38, can be enriched in a semiautomated fashion on reusable, dry-storage, customized antibody cartridges. Using this method, a researcher, with very little hands-on time and in a single day, can perform up to 96 simultaneous enrichments at a similar level of quality as a manual workflow. TOMAHAQ (Triggered by Offset, Multiplexed, Accurate-mass, High-resolution, and Absolute Quantification), a targeted mass spectrometry technique that combines sample multiplexing and high sensitivity, was employed to characterize neoepitopes displayed on MHC-I by tumor cells and to quantitatively assess the influence of neoantigen expression and induced degradation on neoepitope presentation. This unique combination of robust semiautomated MHC-I peptide isolation and high-throughput multiplexed targeted quantitation allows for both the routine analysis of >4000 unique MHC-I peptides from 250 million cells using nontargeted methods, as well as quantitative sensitivity down to the low amol/μl level using TOMAHAQ targeted MS.

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Semiautomated peptide immunoprecipitation on reusable antibody cartridges.

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Application of TOMAHAQ for MHC-I detection and quantitation.

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Routine analysis of >4000 unique MHC-I peptides from 250 million cells via automation.

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Quantitative sensitivity down to the low amol/μl level using TOMAHAQ targeted MS.

Identification and validation of viral antigens sharing sequence and structural homology with tumor-associated antigens (TAAs)

BACKGROUND

The host's immune system develops in equilibrium with both cellular self-antigens and non-self-antigens derived from microorganisms which enter the body during lifetime. In addition, during the years, a tumor may arise presenting to the immune system an additional pool of non-self-antigens, namely tumor antigens (tumor-associated antigens, TAAs; tumor-specific antigens, TSAs).

METHODS

In the present study, we looked for homology between published TAAs and non-self-viral-derived epitopes. Bioinformatics analyses and ex vivo immunological validations have been performed.

RESULTS

Surprisingly, several of such homologies have been found. Moreover, structural similarities between paired TAAs and viral peptides as well as comparable patterns of contact with HLA and T cell receptor (TCR) α and β chains have been observed. Therefore, the two classes of non-self-antigens (viral antigens and tumor antigens) may converge, eliciting cross-reacting CD8+ T cell responses which possibly drive the fate of cancer development and progression.

CONCLUSIONS

An established antiviral T cell memory may turn out to be an anticancer T cell memory, able to control the growth of a cancer developed during the lifetime if the expressed TAA is similar to the viral epitope. This may ultimately represent a relevant selective advantage for patients with cancer and may lead to a novel preventive anticancer vaccine strategy.

Identification and characterization of heteroclitic peptides in TCR-binding positions with improved HLA-binding efficacy

The antigenicity as well as the immunogenicity of tumor associated antigens (TAAs) may need to be potentiated in order to break the immunological tolerance. To this aim, heteroclitic peptides were designed introducing specific substitutions in the residue at position 4 (p4) binding to TCR. The effect of such modifications also on the affinity to the major histocompatibility class I (MHC-I) molecule was assessed. The Trp2 antigen, specific for the mouse melanoma B16F10 cells, as well as the HPV-E7 antigen, specific for the TC1 tumor cell lines, were used as models. Affinity of such heteroclitic peptides to HLA was predicted by bioinformatics tools and the most promising ones were validated by structural conformational and HLA binding analyses. Overall, we demonstrated that TAAs modified at the TCR-binding p4 residue are predicted to have higher affinity to MHC-I molecules. Experimental evaluation confirms the stronger binding, suggesting that this strategy may be very effective for designing new vaccines with improved antigenic efficacy.

Selecting Target Antigens for Cancer Vaccine Development

One of the principal goals of cancer immunotherapy is the development of efficient therapeutic cancer vaccines that are able to elicit an effector as well as memory T cell response specific to tumor antigens. In recent years, the attention has been focused on the personalization of cancer vaccines. However, the efficacy of therapeutic cancer vaccines is still disappointing despite the large number of vaccine strategies targeting different tumors that have been evaluated in recent years. While the preclinical data have frequently shown encouraging results, clinical trials have not provided satisfactory data to date. The main reason for such failures is the complexity of identifying specific target tumor antigens that should be unique or overexpressed only by the tumor cells compared to normal cells. Most of the tumor antigens included in cancer vaccines are non-mutated overexpressed self-antigens, eliciting mainly T cells with low-affinity T cell receptors (TCR) unable to mediate an effective anti-tumor response. In this review, the target tumor antigens employed in recent years in the development of therapeutic cancer vaccine strategies are described, along with potential new classes of tumor antigens such as the human endogenous retroviral elements (HERVs), unconventional antigens, and/or heteroclitic peptides.

Immunoproteasome Genes Are Modulated in CD34+ JAK2V617F Mutated Cells from Primary Myelofibrosis Patients

Primary myelofibrosis (PMF) is a rare myeloproliferative neoplasm characterized by stem-cell-derived clonal over-proliferation of mature myeloid lineages, bone marrow fibrosis, osteosclerosis, defective erythropoiesis, and pro-inflammatory cytokine over-expression. The aim of the present study was to highlight possible differences in the transcriptome among CD34+ cells from peripheral blood (PB) of PMF patients. Therefore, we merged two microarray datasets of healthy control subjects and PMF (34 JAK2V617F MUTATED and 28 JAK2 wild-type). The GO analysis of upregulated genes revealed enrichment for JAK2/STAT1 pathway gene set in PB CD34+ cells of PMF patients with and without the JAK2V617F mutation comparing to the healthy control subjects, and in particular a significant upregulation of immunoproteasome (IP)-belonging genes as PSMB8, PSMB9, and PSMB10. A more detailed investigation of the IFN-gamma (IFNG) pathway also revealed that IFNG, IRF1, and IFNGR2 were significantly upregulated in PB CD34+ cells of PMF patients carrying the mutation for JAK2V617F compared to JAK2 wild-type PMF patients. Finally, we showed an upregulation of HLA-class I genes in PB CD34+ cells from PMF JAK2V617F mutated patients compared to JAK2 wild-type and healthy controls. In conclusion, our results demonstrate that IPs and IFNG pathways could be involved in PMF disease and in particular in patients carrying the JAK2V617F mutation.

A phase I study of multi-HLA-binding peptides derived from heat shock protein 70/glypican-3 and a novel combination adjuvant of hLAG-3Ig and Poly-ICLC for patients with metastatic gastrointestinal cancers: YNP01 trial

Background

This phase I study aimed to evaluate the safety, peptide-specific immune responses, and anti-tumor effects of a novel vaccination therapy comprising multi-HLA-binding heat shock protein (HSP) 70/glypican-3 (GPC3) peptides and a novel adjuvant combination of hLAG-3Ig and Poly-ICLC against metastatic gastrointestinal cancers.

Methods

HSP70/GPC3 peptides with high binding affinities for three HLA types (A*24:02, A*02:01, and A*02:06) were identified with our peptide prediction system. The peptides were intradermally administered with combined adjuvants on a weekly basis. This study was a phase I dose escalation clinical trial, which was carried out in a three patients’ cohort; in total, 11 patients were enrolled for the recommended dose.

Results

Seventeen patients received this vaccination therapy without dose-limiting toxicity. All treatment-related adverse events were of grades 1 to 2. Peptide-specific CTL induction by HSP70 and GPC3 proteins was observed in 11 (64.7%) and 13 (76.5%) cases, respectively, regardless of the HLA type. Serum tumor marker levels were decreased in 10 cases (58.8%). Immunological analysis using PBMCs indicated that patients receiving dose level 3 presented with significantly reduced T cell immunoglobulin and mucin-domain containing-3 (TIM3)-expressing CD4 + T cells after one course of treatment. PD-1 or TIM3-expressing CD4 + T cells and T cell immunoreceptor with immunoglobulin and ITIM domains (TIGIT)-expressing CD8 + T cells in PBMCs before vaccination were negative predictive factors for survival.

Conclusions

This novel peptide vaccination therapy was safe for patients with metastatic gastrointestinal cancers.

Electronic supplementary material

The online version of this article (10.1007/s00262-020-02518-7) contains supplementary material, which is available to authorized users.

An altered HLA-A0201-restricted MUC1 epitope that could induce more efficient anti-tumor effects against gastric cancer

MUC1 is a tumor-associated antigen (TAA) overexpressed in many tumor types, which makes it an attractive target for cancer immunotherapy. However, this marker is a non-mutated antigen without high immunogenicity. In this study, we designed several new altered peptides by replacing amino acids in their sequences, which were derived from a low-affinity MUC1 peptide, thus bypassing immune tolerance. Compared to the wild-type (WT) peptide, the altered MUC1 peptides (MUC1_1081-1089L2, MUC1_1156-1164L2, MUC1_1068-1076Y1) showed higher affinity to the HLA-A0201 molecule and stronger immunogenicity. Furthermore, these altered peptides resulted in the generation of more cytotoxic T lymphocytes (CTLs) that could cross-recognize gastric cancer cells expressing WT MUC1 peptides, in an HLA-A0201-restricted manner. In addition, M1.1 (MUC1_950-958), a promising antitumor peptide that has been tested in multiple tumors, was not able to induce stronger antitumor responses. Collectively, our results demonstrated that altered peptides from MUC1, as potential HLA-A0201-restricted CTL epitopes, could serve as peptide vaccines or constitute components of peptide-loaded dendritic cell vaccines for gastric cancer treatment.

Phase I/II clinical trial of a Wilms' tumor 1-targeted dendritic cell vaccination-based immunotherapy in patients with advanced cancer

Dendritic cell (DC)-based immunotherapies have been created for a broad expanse of cancers, and DC vaccines prepared with Wilms' tumor protein 1 (WT1) peptides have shown great therapeutic efficacy in these diseases. In this paper, we report the results of a phase I/II study of a DC-based vaccination for advanced breast, ovarian, and gastric cancers, and we offer evidence that patients can be effectively vaccinated with autologous DCs pulsed with WT1 peptide. There were ten patients who took part in this clinical study; they were treated biweekly with a WT1 peptide-pulsed DC vaccination, with toxicity and clinical and immunological responses as the principal endpoints. All of the adverse events to DC vaccinations were tolerable under an adjuvant setting. The clinical response was stable disease in seven patients. Karnofsky Performance Scale scores were enhanced, and computed tomography scans revealed tumor shrinkage in three of seven patients. Human leukocyte antigen (HLA)/WT1-tetramer and cytoplasmic IFN-γ assays were used to examine the induction of a WT-1-specific immune response. The immunological responses to DC vaccination were significantly correlated with fewer myeloid-derived suppressor cells (P = 0.045) in the pretreated peripheral blood. These outcomes offered initial clinical evidence that the WT1 peptide-pulsed DC vaccination is a potential treatment for advanced cancer.

Co-inhibition of TIGIT, PD1, and Tim3 reverses dysfunction of Wilms tumor protein-1 (WT1)-specific CD8+ T lymphocytes after dendritic cell vaccination in gastric cancer

Dendritic cell (DC) vaccines have been shown to stimulate tumor antigen-specific CD8+ T cells; however, this strategy has demonstrated variable clinical efficacy likely due to immune escape mechanisms that can induce tumor-specific CD8+ T cell dysfunction. Herein, we evaluated the functional characteristics of DC vaccine-induced CD8+ T cells with regard to immune checkpoint inhibitors in gastric cancer patients who were administered Wilms tumor protein-1 (WT1)-targeted DC vaccine. We observed the upregulation of the inhibitory molecule, TIGIT and the inhibitory T cell co-receptors PD1 and Tim3 in limiting WT1-specific CD8+ T cell growth and function in GC patients. TIGIT-expressing PD1+Tim3- CD8+ T cells were the largest subset, while TIGIT+PD1+Tim3+ was the most dysfunctional subset of WT1-specific CD8+ T cells in gastric cancer patients. Importantly, the co-inhibition of TIGIT, PD1, and Tim3 pathways enhanced the growth, proliferation, and cytokine production of WT1-specific CD8+ T cells. In conclusion, our data suggests that targeting TIGIT, PD1, and Tim3 pathways may be important in reversing immune escape in patients with advanced gastric cancer.