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Photoimmunotherapy faces challenges due to insufficient intratumoral accumulation of photothermal agents and the reversion of the cancer‐immunity cycle during treatment. In this study, an anti‐PD‐L1‐immobilized magnetic gold nanohut, AuNH‐2‐Ab, with photoresponsive, thermosensitive, and immunomodulatory properties to effectively suppress the growth of primary tumors, elevate immunogenic cell death (ICD) levels, reverse the tumor immune microenvironment (TIME), and consequently inhibit metastases are developed. AuNH‐2‐Ab achieves high tumor accumulation (9.54% injected dose) following systemic administration, allowing the modulation of hyperthermia dose of over 50 °C in the tumor. By optimizing the hyperthermia dose, AuNH‐2‐Ab simultaneously target and eliminate cancer cells and tumor‐associated macrophages, thereby activating potent antitumor immunity without being compromised by immunosuppressive elements. Hyperthermia/pH induced morphological transformation of AuNH‐2‐Ab involving the detachment of the surface antibody for in situ PD‐L1 inhibition, and exposure of the inner fucoidan layer for natural killer (NK) cell activation. This precision photoimmunotherapy approach reprograms the TIME, significantly prolongs survival in a murine hepatocellular carcinoma model (Hep55.1c), and harnesses the synergistic effects of ICD production and checkpoint inhibitors by utilizing a single nanoplatform. [ABSTRACT FROM AUTHOR]

Background: Desmoplastic melanoma (DM) is a rare subtype of melanoma characterized by high immunogenicity which makes it particularly suitable for immune checkpoint inhibitors (ICIs) treatment. Case presentation: We report the case of a 53-year-old man with metastatic DM successfully treated with the combination of anti-CTLA-4 and anti-PD-1 antibodies, who developed serious immune-related adverse events (irAEs). The primary tumor was characterized by absent PD-L1 expression and no-brisk lymphocytes infiltration. NGS showed absence of BRAF mutation, a high tumor mutational burden, and an UV-induced DNA damage signature. Metastatic lesions regressed rapidly after few cycles of ICIs until complete response, however the patient developed serious irAEs including hypothyroidism, adrenal deficiency, and acute interstitial nephritis which led to the definitive suspension of treatment. Currently, the patient has normal renal functionality and no disease relapse after 26 months from starting immunotherapy, and after 9 months from its definitive suspension. Conclusion: Efficacy and toxicity are two sides of the same coin of high sensitivity to ICIs in DM. For this reason, these patients should be closely monitored during ICIs therapy to promptly identify serious side effects and to correctly manage them. [ABSTRACT FROM AUTHOR]

Abstract Photoimmunotherapy faces challenges due to insufficient intratumoral accumulation of photothermal agents and the reversion of the cancer‐immunity cycle during treatment. In this study, an anti‐PD‐L1‐immobilized magnetic gold nanohut, AuNH‐2‐Ab, with photoresponsive, thermosensitive, and immunomodulatory properties to effectively suppress the growth of primary tumors, elevate immunogenic cell death (ICD) levels, reverse the tumor immune microenvironment (TIME), and consequently inhibit metastases are developed. AuNH‐2‐Ab achieves high tumor accumulation (9.54% injected dose) following systemic administration, allowing the modulation of hyperthermia dose of over 50 °C in the tumor. By optimizing the hyperthermia dose, AuNH‐2‐Ab simultaneously target and eliminate cancer cells and tumor‐associated macrophages, thereby activating potent antitumor immunity without being compromised by immunosuppressive elements. Hyperthermia/pH induced morphological transformation of AuNH‐2‐Ab involving the detachment of the surface antibody for in situ PD‐L1 inhibition, and exposure of the inner fucoidan layer for natural killer (NK) cell activation. This precision photoimmunotherapy approach reprograms the TIME, significantly prolongs survival in a murine hepatocellular carcinoma model (Hep55.1c), and harnesses the synergistic effects of ICD production and checkpoint inhibitors by utilizing a single nanoplatform.

BackgroundDesmoplastic melanoma (DM) is a rare subtype of melanoma characterized by high immunogenicity which makes it particularly suitable for immune checkpoint inhibitors (ICIs) treatment.Case presentationWe report the case of a 53-year-old man with metastatic DM successfully treated with the combination of anti-CTLA-4 and anti-PD-1 antibodies, who developed serious immune-related adverse events (irAEs). The primary tumor was characterized by absent PD-L1 expression and no-brisk lymphocytes infiltration. NGS showed absence of BRAF mutation, a high tumor mutational burden, and an UV-induced DNA damage signature. Metastatic lesions regressed rapidly after few cycles of ICIs until complete response, however the patient developed serious irAEs including hypothyroidism, adrenal deficiency, and acute interstitial nephritis which led to the definitive suspension of treatment. Currently, the patient has normal renal functionality and no disease relapse after 26 months from starting immunotherapy, and after 9 months from its definitive suspension.ConclusionEfficacy and toxicity are two sides of the same coin of high sensitivity to ICIs in DM. For this reason, these patients should be closely monitored during ICIs therapy to promptly identify serious side effects and to correctly manage them.

Peripheral T-cell lymphoma (PTCL) and natural killer/T-cell lymphoma (NKTCL) are rare subtypes of non-Hodgkin’s lymphoma that are typically associated with poor treatment outcomes. Contemporary first-line treatment strategies generally involve the use of combination chemoimmunotherapy, radiation and/or stem cell transplant. Salvage options incorporate a number of novel agents including epigenetic therapies (e.g. HDAC inhibitors, DNMT inhibitors) as well as immune checkpoint inhibitors. However, validated biomarkers to select patients for individualized precision therapy are presently lacking, resulting in high treatment failure rates, unnecessary exposure to drug toxicities, and missed treatment opportunities. Recent advances in research on the tumor and microenvironmental factors of PTCL and NKTCL, including alterations in specific molecular features and immune signatures, have improved our understanding of these diseases, though several issues continue to impede progress in clinical translation. In this Review, we summarize the progress and development of the current predictive biomarker landscape, highlight potential knowledge gaps, and discuss the implications on novel therapeutics development in PTCL and NKTCL. [ABSTRACT FROM AUTHOR]

Although tumour PD-L1 (CD274) expression had been used as a predictive biomarker in checkpoint immunotherapy targeting the PD1/PD-L1 axis in various cancers, the regulation of PD-L1 (CD274) expression is unclear. Yes-associated protein (YAP), an important oncogenic protein in Hippo signalling pathway, reportedly promotes cancer development. We investigated whether inhibition of YAP down-regulates PD-L1 (CD274) in human malignant pleural mesothelioma (MPM). Western blotting showed that 2 human MPM cell lines (H2052 and 211H) had increased PD-L1 protein expression compared to H290, MS-1 and H28 cells. In H2052 and 211H cells, PD-L1 mRNA expression was significantly increased compared to other MPM cell lines; YAP knockdown by small interfering RNA decreased PD-L1 protein and mRNA expression. Forced overexpression of the YAP gene increased PD-L1 protein expression in H2452 cells. Chromatin immunoprecipitation (ChIP) assay showed the precipitation of PD-L1 enhancer region encompassing 2 putative YAP-TEAD-binding sites in H2052 cells. We found that, in human MPM tissue microarray samples, YAP and PD-L1 concurrently expressed in immunohistochemistry stain (n = 70, P

Immune checkpoint inhibitors (ICI) targeting the PD-1/PD-L1 axis have changed the treatment paradigm for advanced solid tumors; however, many patients experience treatment resistance. In preclinical models 4-1BB co-stimulation synergizes with ICI by activating cytotoxic T- and NK-cell-mediated anti-tumor immunity. Here we characterize the mechanism of action of a mouse-reactive Fc-inert PD-L1×4-1BB bispecific antibody (mbsAb-PD-L1×4-1BB) and provide proof-of-concept for enhanced anti-tumor activity. In reporter assays mbsAb-PD-L1×4-1BB exhibited conditional 4-1BB agonist activity that was dependent on simultaneous binding to PD-L1. mbsAb-PD-L1×4-1BB further blocked the PD-L1/PD-1 interaction independently of 4-1BB binding. By combining both mechanisms, mbsAb-PD-L1×4-1BB strongly enhanced T-cell proliferation, cytokine production and antigen-specific cytotoxicity using primary mouse cells in vitro. Furthermore, mbsAb-PD-L1×4-1BB exhibited potent anti-tumor activity in the CT26 and MC38 models in vivo, leading to the rejection of CT26 tumors that were unresponsive to PD-L1 blockade alone. Anti-tumor activity was associated with increased tumor-specific CD8+ T cells and reduced regulatory T cells within the tumor microenvironment and tumor-draining lymph nodes. In immunocompetent tumor-free mice, mbsAb-PD-L1×4-1BB treatment neither induced T-cell infiltration into the liver nor elevated liver enzymes in the blood. Dual targeting of PD-L1 and 4-1BB with a bispecific antibody may therefore address key limitations of first generation 4-1BB-agonistic antibodies, and may provide a novel approach to improve PD-1/PD-L1 checkpoint blockade.

Tumor-associated tertiary lymphoid structures are ectopic lymphoid aggregates that have considerable morphological, cellular, and molecular similarity to secondary lymphoid organs, particularly lymph nodes. Tumor vessels expressing peripheral node addressin (PNAd) are hallmark features of these structures. Previous work from our laboratory demonstrated that PNAd is displayed on intratumoral vasculature of murine tumors, and its expression is controlled by the engagement of lymphotoxin-a3, secreted by effector CD8 T cells, with tumor necrosis factor receptors (TNFR) on tumor endothelial cells (TEC). The goals of the present work were: 1) to identify differences in expression of genes encoding the scaffolding proteins and glycosyl transferases associated with PNAd biosynthesis in TEC and lymph node blood endothelial cells (LN BEC); and 2) to determine which of these PNAd associated components are regulated by TNFR signaling. We found that the same genes encoding scaffolding proteins and glycosyl transferases were upregulated in PNAd+ LN BEC and PNAd+ TEC relative to their PNAdneg counterparts. The lower level of PNAd expression on TEC vs LN BEC was associated with relatively lower expression of these genes, particularly the carbohydrate sulfotransferase Chst4. Loss of PNAd on TEC in the absence of TNFR signaling was associated with lack of upregulation of these same genes. A small subset of PNAd+ TEC remaining in the absence of TNFR signaling showed normal upregulation of a subset of these genes, but reduced upregulation of genes encoding the scaffolding proteins podocalyxin and nepmucin, and carbohydrate sulfotransferase Chst2. Lastly, we found that checkpoint immunotherapy augmented both the fraction of TEC expressing PNAd and their surface level of this ligand. This work points to strong similarities in the regulation of PNAd expression on TEC by TNFR signaling and on LN BEC by lymphotoxin-b receptor signaling, and provides a platform for the development of novel strategies that manipulate PNAd expression on tumor vasculature as an element of cancer immunotherapy. [ABSTRACT FROM AUTHOR]

Background: Immune checkpoint therapy (ICT) has significantly impacted the treatment of malignant pleural mesothelioma (MPM). Despite some promising results from combination therapies, nearly half of MPM patients do not benefit, underscoring the urgent need for reliable predictive biomarkers. This study assesses the prognostic value of serum soluble mesothelin-related peptide (SMRP) and PD-L1 levels in MPM patients receiving ICT., Methods: We conducted a retrospective analysis of 125 MPM patients treated with ICT by measuring pre-ICT serum levels of SMRP and PD-L1. We also examined the correlation of these serum levels with tumor mRNA expressions of mesothelin and PD-L1. Both univariable and multivariable Cox regression analyses were used to determine independent prognosticators for overall survival (OS). A prospective ICT clinical trial and our historical cohort were included for validation., Results: Seventy-seven patients (62%) were treated with either anti-PD-(L)1 monotherapy, and the remaining 38% received combination ICT. Higher pre-ICT SMRP levels were observed in epithelioid MPM compared to nonepithelioid MPM. Serum PD-L1 levels did not differ significantly between the different histologic groups. Univariable analysis identified durable clinical benefit, development of immune-related adverse events, and SMRP levels as significantly associated with OS. Multivariable analysis confirmed SMRP as an independent prognostic factor, with lower levels (≤1.35 nmol/L) correlating with improved OS. The association of high SMRP with worse prognosis was validated in the prospective ICT clinical trial cohort and not in our historical cohort treated without ICT., Conclusions: SMRP is a promising serum biomarker for predicting survival in MPM patients treated with ICT and warrants prospective investigation., Competing Interests: Conflict of Interest Statement H.S.L. reports research funding from the National Institutes of Health, the Department of Defense, the Cancer Prevention Research Institute of Texas, the Helis Medical Research Foundation, and Dan L. Duncan Comprehensive Cancer Center, and investigator-initiated preclinical and clinical research funding from Samyang Biopharm and Momotaro-Gene. B.M.B. reports research funding from the National Institute of Health and Cancer Prevention Research Institute of Texas; clinical trial funding from AstraZeneca, Novartis, and Momotaro-Gene; and serving as a consultant in non–small cell lung cancer for AstraZeneca. R.T.R. reports research support from the National Institutes of Health, the American Association of Thoracic Surgery, and the DeGregorio Family Foundation; serving on the board of directors of the Mesothelioma Applied Research Foundation (nonremunerated); and providing expert legal opinion and serving on a speakers bureau for Merck. S.H.B has received IIT funding from Natera, Steris, and Medtronic; codeveloped instruments with Scanlan and holds other patents with Mayo Clinic; and has served as a speaker for Medtronic, AstraZeneca, and Medela. S.S.G. reports proctor and speaker honoraria from Intuitive Surgical. All other authors reported no conflicts of interest. The Journal policy requires editors and reviewers to disclose conflicts of interest and to decline handling or reviewing manuscripts for which they may have a conflict of interest. The editors and reviewers of this article have no conflicts of interest., (Copyright © 2024 The American Association for Thoracic Surgery. Published by Elsevier Inc. All rights reserved.)

Tumor-associated tertiary lymphoid structures are ectopic lymphoid aggregates that have considerable morphological, cellular, and molecular similarity to secondary lymphoid organs, particularly lymph nodes. Tumor vessels expressing peripheral node addressin (PNAd) are hallmark features of these structures. Previous work from our laboratory demonstrated that PNAd is displayed on intratumoral vasculature of murine tumors, and its expression is controlled by the engagement of lymphotoxin-α3, secreted by effector CD8 T cells, with tumor necrosis factor receptors (TNFR) on tumor endothelial cells (TEC). The goals of the present work were: 1) to identify differences in expression of genes encoding the scaffolding proteins and glycosyl transferases associated with PNAd biosynthesis in TEC and lymph node blood endothelial cells (LN BEC); and 2) to determine which of these PNAd associated components are regulated by TNFR signaling. We found that the same genes encoding scaffolding proteins and glycosyl transferases were upregulated in PNAd+ LN BEC and PNAd+ TEC relative to their PNAdneg counterparts. The lower level of PNAd expression on TEC vs LN BEC was associated with relatively lower expression of these genes, particularly the carbohydrate sulfotransferase Chst4. Loss of PNAd on TEC in the absence of TNFR signaling was associated with lack of upregulation of these same genes. A small subset of PNAd+ TEC remaining in the absence of TNFR signaling showed normal upregulation of a subset of these genes, but reduced upregulation of genes encoding the scaffolding proteins podocalyxin and nepmucin, and carbohydrate sulfotransferase Chst2. Lastly, we found that checkpoint immunotherapy augmented both the fraction of TEC expressing PNAd and their surface level of this ligand. This work points to strong similarities in the regulation of PNAd expression on TEC by TNFR signaling and on LN BEC by lymphotoxin-β receptor signaling, and provides a platform for the development of novel strategies that manipulate PNAd expression on tumor vasculature as an element of cancer immunotherapy.

Simple Summary: The cyclin E/CDK2 complex may present a promising target axis for the treatment of triple-negative breast cancers (TNBC); however, therapeutically relevant doses of CDK2 inhibitors have been associated with toxicities. Here, we report that the suboptimal dosing of the CDK 2, 7 and 9 inhibitor SNS-032 reduced the viability of TNBC cells and upregulated the checkpoint ligand PD-L1 expression in surviving cancer cells in vitro and in human orthotopic MDA-MB-231 TNBC xenografts grown in immunodeficient mice. Moreover, in immunodeficient, TNBC xenograft-bearing mice engrafted with human immune cells, SNS-032 treatment was associated with the infiltration of CD45+ human immune cells in tumors. In these orthotopic MDA-MB-231 TNBC-bearing mice, suboptimal SNS-032 doses given sequentially ahead of dosing with the anti-PD-L1 antibody avelumab significantly restricted tumor growth compared with monotherapy. These findings suggest that surviving cancer cells following suboptimal CDK inhibitor treatment may be responsive to checkpoint immunotherapy. Triple-negative breast cancers (TNBC) expressing PD-L1 qualify for checkpoint inhibitor immunotherapy. Cyclin E/CDK2 is a potential target axis in TNBC; however, small-molecule drugs at efficacious doses may be associated with toxicity, and treatment alongside immunotherapy requires investigation. We evaluated CDK inhibition at suboptimal levels and its anti-tumor and immunomodulatory effects. Transcriptomic analyses of primary breast cancers confirmed higher cyclin E/CDK2 expression in TNBC compared with non-TNBC. Out of the three CDK2-targeting inhibitors tested, the CDK 2, 7 and 9 inhibitor SNS-032 was the most potent in reducing TNBC cell viability and exerted cytotoxicity against all eight TNBC cell lines evaluated in vitro. Suboptimal SNS-032 dosing elevated cell surface PD-L1 expression in surviving TNBC cells. In mice engrafted with human immune cells and challenged with human MDA-MB-231 TNBC xenografts in mammary fat pads, suboptimal SNS-032 dosing partially restricted tumor growth, enhanced the tumor infiltration of human CD45+ immune cells and elevated cell surface PD-L1 expression in surviving cancer cells. In tumor-bearing mice engrafted with human immune cells, the anti-PD-L1 antibody avelumab, given sequentially following suboptimal SNS-032 dosing, reduced tumor growth compared with SNS-032 alone or with avelumab without prior SNS-032 priming. CDK inhibition at suboptimal doses promotes immune cell recruitment to tumors, PD-L1 expression by surviving TNBC cells and may complement immunotherapy. [ABSTRACT FROM AUTHOR]

Abstract Background Immune checkpoint inhibitor (ICI) induced myocarditis is a rare, severe, and often fatal adverse event. Evidence to guide appropriate immunosuppressive therapy is scarce. We present a case of ICI-induced myocarditis and a review of ICI-induced myocarditis cases to determine the most effective immunosuppressive therapeutic strategy for ICI-induced myocarditis. Methods A systematic search of PubMed was carried out for treatment of ICI-induced myocarditis. Reference lists from identified articles were manually reviewed for additional cases. Results A total of 87 cases with ICI-induced myocarditis were identified. The majority were melanoma (n = 39), lung cancer (n = 19), renal cell cancer (n = 10), and thymoma cancer patients (n = 4). In 38 (44%) cases, patients received high-dose steroid treatment only. A total of 49 (56%) cases were treated with immunosuppressive agents other than steroid; a total of 13 different immunosuppressive agents were used, including alemtuzumab or abatacept. The median time to onset of symptoms after initiation of ICI was 16 days (range, 1–196 days); cardiotoxic symptoms developed after 2 cycles of ICI (range, 1–13 cycles). A total of 48% of cases were fatal. In cases treated with high-dose steroids only vs. cases treated with other immunosuppressive agents, fatality was 55% and 43% respectively. In 64 out of the 87 cases, tumor control was not described. In patients treated with high-dose steroids only, two patients had stable disease as best tumor response; in patients treated with other immunosuppressive agents, one complete response, one partial response and seven stable disease were noted as best tumor response. Overall, 11 studies were at low risk of bias (12.6%), 38 at moderate risk of bias (43.7%) and 38 at high risk of bias (43.7%). Conclusion Immune checkpoint inhibitor induced myocarditis is a serious and often fatal adverse event. High-dose prednisolone, alemtuzumab or abatacept are all possible treatments options for ICI-induced myocarditis, whereas infliximab increases the risk of death from cardiovascular causes, and should be avoided. Further research is needed.

Immune checkpoint inhibitors (ICI) targeting the PD-1/PD-L1 axis have changed the treatment paradigm for advanced solid tumors; however, many patients experience treatment resistance. In preclinical models 4-1BB co-stimulation synergizes with ICI by activating cytotoxic T- and NK-cell-mediated anti-tumor immunity. Here we characterize the mechanism of action of a mouse-reactive Fc-inert PD-L1×4-1BB bispecific antibody (mbsAb-PD-L1×4-1BB) and provide proof-of-concept for enhanced anti-tumor activity. In reporter assays mbsAb-PD-L1×4-1BB exhibited conditional 4-1BB agonist activity that was dependent on simultaneous binding to PD-L1. mbsAb-PD-L1×4-1BB further blocked the PD-L1/PD-1 interaction independently of 4-1BB binding. By combining both mechanisms, mbsAb-PD-L1×4-1BB strongly enhanced T-cell proliferation, cytokine production and antigen-specific cytotoxicity using primary mouse cells in vitro. Furthermore, mbsAb-PD-L1×4-1BB exhibited potent anti-tumor activity in the CT26 and MC38 models in vivo, leading to the rejection of CT26 tumors that were unresponsive to PD-L1 blockade alone. Anti-tumor activity was associated with increased tumor-specific CD8+ T cells and reduced regulatory T cells within the tumor microenvironment and tumor-draining lymph nodes. In immunocompetent tumor-free mice, mbsAb-PD-L1×4-1BB treatment neither induced T-cell infiltration into the liver nor elevated liver enzymes in the blood. Dual targeting of PD-L1 and 4-1BB with a bispecific antibody may therefore address key limitations of first generation 4-1BB-agonistic antibodies, and may provide a novel approach to improve PD-1/PD-L1 checkpoint blockade. [ABSTRACT FROM AUTHOR]

Abstract Objective NUT midline carcinoma (NMC), a rare type of squamous cell carcinoma, is genetically characterised by NUT midline carcinoma family member 1 (NUTM1) gene rearrangement. NMC can arise from the lungs; however, there is no standard for the management of primary pulmonary NMC. This study aimed to confirm the clinical features and report the treatments, especially with immune checkpoint inhibitors (ICIs), and outcomes of patients with primary pulmonary NMC. Methods A retrospective review of patients with primary pulmonary NMC was performed in the First Affiliated Hospital of Guangzhou Medical University between January 2015 and December 2018. Clinical manifestations as well as radiographic and pathological findings were recorded. Whole-exome sequencing (WES), a predictor for ICI response, was used to determine the tumour mutational burden (TMB). Treatments, especially by immune checkpoint blockade, and patient survival were analysed. Results Seven patients with primary pulmonary mass (four men and three women) with a mean age of 42 years (range, 23–74) who were diagnosed with NMC according to NUT immunohistochemistry staining were included for analysis. One patient had a rare fusion of CHRM5-NUTM1 by tumour sequencing. A wide range of TMB (1.75–73.81 mutations/Mbp) was observed. The initial treatments included chemotherapy (5/7, 71.4%), surgery (1/7, 14.3%), and radiotherapy (1/7, 14.3%). Five patients (5/7, 71.4%) received ICIs (programmed cell death protein 1 [PD1]/programmed cell death ligand 1 [PDL1] monoclonal antibody) as second- or higher-line treatments. The median overall survival (OS) was 4.1 months (range, 1.5–26.7 months). Conclusions Patients with primary pulmonary NMC have a poor prognosis and chemotherapy is often preferred. Checkpoint immunotherapy is a good option as the second- or higher-line treatment. TMB seems to be not associated with OS.

ABSTRACT Interest in host-directed therapies as alternatives/adjuncts to antibiotic treatment has resurged with the increasing prevalence of antibiotic-resistant tuberculosis (TB). Immunotherapies that reinvigorate immune responses by targeting immune checkpoints like PD-1/PD-L1 have proved successful in cancer therapy. Immune cell inhibitory receptors that trigger Mycobacterium tuberculosis-specific immunosuppression, however, are unknown. Here, we show that the levels of CD84, a SLAM family receptor, increase in T and B cells in lung tissues from M. tuberculosis-infected C57BL/6 mice and in peripheral blood mononuclear cells (PBMCs) from pulmonary TB patients. M. tuberculosis challenge experiments using CD84-deficient C57BL/6 mice suggest that CD84 expression likely leads to T and B cell immunosuppression during M. tuberculosis pathogenesis and also plays an inhibitory role in B cell activation. Importantly, CD84-deficient mice showed improved M. tuberculosis clearance and longer survival than M. tuberculosis-infected wild-type (WT) mice. That CD84 is a putative M. tuberculosis infection-specific inhibitory receptor suggests it may be a suitable target for the development of TB-specific checkpoint immunotherapies. IMPORTANCE Immune checkpoint therapies, such as targeting checkpoints like PD-1/PD-L1, have proved successful in cancer therapy and can reinvigorate immune responses. The potential of this approach for treating chronic infectious diseases like TB has been recognized, but a lack of suitable immunotherapeutic targets, i.e., immune cell inhibitory receptors that trigger immunosuppression specifically during Mycobacterium tuberculosis pathogenesis, has limited the application of this strategy in the development of new TB therapies. Our focus in this study was to address this gap and search for an M. tuberculosis-specific checkpoint target. Our results suggest that CD84 is a putative inhibitory receptor that may be a suitable target for the development of TB-specific checkpoint immunotherapies.

Background: Malignant gliomas are deadly tumours with few therapeutic options. Although immunotherapy may be a promising therapeutic strategy for treating gliomas, a significant barrier is the CD11b+ tumour-associated myeloid cells (TAMCs), a heterogeneous glioma infiltrate comprising up to 40% of a glioma's cellular mass that inhibits anti-tumour T-cell function and promotes tumour progression. A theranostic approach uses a single molecule for targeted radiopharmaceutical therapy (TRT) and diagnostic imaging; however, there are few reports of theranostics targeting the tumour microenvironment. Methods: Utilizing a newly developed bifunctional chelator, Lumi804, an anti-CD11b antibody (αCD11b) was readily labelled with either Zr-89 or Lu-177, yielding functional radiolabelled conjugates for PET, SPECT, and TRT. Findings: 89Zr/177Lu-labeled Lumi804-αCD11b enabled non-invasive imaging of TAMCs in murine gliomas. Additionally, 177Lu-Lumi804-αCD11b treatment reduced TAMC populations in the spleen and tumour and improved the efficacy of checkpoint immunotherapy. Interpretation: 89Zr- and 177Lu-labeled Lumi804-αCD11b may be a promising theranostic pair for monitoring and reducing TAMCs in gliomas to improve immunotherapy responses. Funding: A full list of funding bodies that contributed to this study can be found in the Acknowledgements section.

BackgroundProteins containing the caspase recruitment domain (CARD) play critical roles in cell apoptosis and immunity. However, the impact of CARD genes in tumor immune cell infiltration, responsiveness to checkpoint immunotherapy, and clinical outcomes of gliomas remains unclear. Here, we explore using CARD genes to depict the immune microenvironment and predict the responsiveness of gliomas to anti-PD-1 therapy.MethodsThe genome and transcriptome data of 231 patients with isocitrate dehydrogenase wild-type (IDH-wt) gliomas were retrieved from The Cancer Genome Atlas (TCGA) database to screen CARD genes associated with T lymphocyte infiltration in gliomas. Weighted co-expression network and LASSO penalized regression were employed to generate a CARD-associated risk score (CARS). Two independent and publicly available datasets were used to validate the effectiveness of CARS.ResultsThe CARS divided the 231 glioma patients into high- and low-risk subgroups with distinct immune microenvironment and molecular features. The high-risk group had high CARS and was characterized by enrichment of dysfunctional T lymphocytes in a profound immunosuppressive microenvironment, whereas the low-risk group had low CARS and exhibited an immune exclusion genotype. Moreover, signaling aberrations including upregulation of PI3K/Akt/mTOR, NF-κB, and TGF-β were found in the high-risk group. In contrast, the activated WNT pathway was more evident in the low-risk group. Furthermore, we found that an elevated CARS indicated a decreased overall survival for IDH-wt gliomas under standard care but a clinical benefit from checkpoint immunotherapy.ConclusionThis study developed an immune- and prognosis-relevant risk score, which could be used to enhance our understanding of the heterogeneity of immune microenvironment of gliomas and facilitate to identify patients who will benefit from checkpoint immunotherapy.

Immunotherapies have revolutionized cancer treatment. In particular, immune checkpoint therapy (ICT) leads to durable responses in some patients with some cancers. However, the majority of treated patients do not respond. Understanding immune mechanisms that underlie responsiveness to ICT will help identify predictive biomarkers of response and develop treatments to convert non-responding patients to responding ones. ICT primarily acts at the level of adaptive immunity. The specificity of adaptive immune cells, such as T and B cells, is determined by antigen-specific receptors. T cell repertoires can be comprehensively profiled by high-throughput sequencing at the bulk and single-cell level. T cell receptor (TCR) sequencing allows for sensitive tracking of dynamic changes in antigen-specific T cells at the clonal level, giving unprecedented insight into the mechanisms by which ICT alters T cell responses. Here, we review how the repertoire influences response to ICT and conversely how ICT affects repertoire diversity. We will also explore how changes to the repertoire in different anatomical locations can better correlate and perhaps predict treatment outcome. We discuss the advantages and limitations of current metrics used to characterize and represent TCR repertoire diversity. Discovery of predictive biomarkers could lie in novel analysis approaches, such as network analysis of amino acids similarities between TCR sequences. Single-cell sequencing is a breakthrough technology that can link phenotype with specificity, identifying T cell clones that are crucial for successful ICT. The field of immuno-sequencing is rapidly developing and cross-disciplinary efforts are required to maximize the analysis, application, and validation of sequencing data. Unravelling the dynamic behavior of the TCR repertoire during ICT will be highly valuable for tracking and understanding anti-tumor immunity, biomarker discovery, and ultimately for the development of novel strategies to improve patient outcomes.

Objective: NUT midline carcinoma (NMC), a rare type of squamous cell carcinoma, is genetically characterised by NUT midline carcinoma family member 1 (NUTM1) gene rearrangement. NMC can arise from the lungs; however, there is no standard for the management of primary pulmonary NMC. This study aimed to confirm the clinical features and report the treatments, especially with immune checkpoint inhibitors (ICIs), and outcomes of patients with primary pulmonary NMC.Methods: A retrospective review of patients with primary pulmonary NMC was performed in the First Affiliated Hospital of Guangzhou Medical University between January 2015 and December 2018. Clinical manifestations as well as radiographic and pathological findings were recorded. Whole-exome sequencing (WES), a predictor for ICI response, was used to determine the tumour mutational burden (TMB). Treatments, especially by immune checkpoint blockade, and patient survival were analysed.Results: Seven patients with primary pulmonary mass (four men and three women) with a mean age of 42 years (range, 23-74) who were diagnosed with NMC according to NUT immunohistochemistry staining were included for analysis. One patient had a rare fusion of CHRM5-NUTM1 by tumour sequencing. A wide range of TMB (1.75-73.81 mutations/Mbp) was observed. The initial treatments included chemotherapy (5/7, 71.4%), surgery (1/7, 14.3%), and radiotherapy (1/7, 14.3%). Five patients (5/7, 71.4%) received ICIs (programmed cell death protein 1 [PD1]/programmed cell death ligand 1 [PDL1] monoclonal antibody) as second- or higher-line treatments. The median overall survival (OS) was 4.1 months (range, 1.5-26.7 months).Conclusions: Patients with primary pulmonary NMC have a poor prognosis and chemotherapy is often preferred. Checkpoint immunotherapy is a good option as the second- or higher-line treatment. TMB seems to be not associated with OS. [ABSTRACT FROM AUTHOR]

To better understand intrinsic resistance to immune checkpoint blockade (ICB), we established a comprehensive view of the cellular architecture of the treatment-naive melanoma ecosystem and studied its evolution under ICB. Using single-cell, spatial multi-omics, we showed that the tumor microenvironment promotes the emergence of a complex melanoma transcriptomic landscape. Melanoma cells harboring a mesenchymal-like (MES) state, a population known to confer resistance to targeted therapy, were significantly enriched in early on-treatment biopsies from non-responders to ICB. TCF4 serves as the hub of this landscape by being a master regulator of the MES signature and a suppressor of the melanocytic and antigen presentation transcriptional programs. Targeting TCF4 genetically or pharmacologically, using a bromodomain inhibitor, increased immunogenicity and sensitivity of MES cells to ICB and targeted therapy. We thereby uncovered a TCF4-dependent regulatory network that orchestrates multiple transcriptional programs and contributes to resistance to both targeted therapy and ICB in melanoma. [Display omitted] • Drug-naive human melanomas contain cancer cells in a MES state • Melanoma cells in the MES state are enriched in on-treatment lesions refractory to ICB • TCF4 promotes the MES while suppressing the melanocytic and antigen presentation programs • Targeting TCF4 expression increases sensitivity to ICB and targeted therapy Single-cell and spatial multi-omics analyses of patient biopsies highlight the association of a mesenchymal-like (MES) state, previously known to confer resistance to targeted therapy, with resistance to immunotherapy in human melanoma and the importance of TCF4 in orchestrating multiple transcriptional programs to confer immune tolerance to MES cells. [ABSTRACT FROM AUTHOR]

Immunotherapy is reportedly effective in a subset of colorectal cancers (CRCs) with high microsatellite instability (MSI-H). Exploring the expression patterns and clinical values of immunologic molecules is critical in defining the specific responsive candidates. Here, we performed comprehensive molecular profiling of the B7 and TNFR family genes across 6 CRC datasets with over 1,000 patients’ details using cBioPortal TCGA data. About 20% of patients had B7 and TNFR family gene alterations. The frequency of B7 gene mutations (2.2%–5%) were similar to copy number alterations (0.53%–5.46%). TNFR amplifications were relatively more common (5.45–11.32%) than that of B7 (0.09–2.73%). B7 and TNFR gene mRNAs were upregulated in 26% of cases (102/379) and 16% of cases (61/379), respectively. The mRNA levels of B7 and TNFR genes were inversely correlated with promoter methylation status. Clinically, both B7-H3 and TNFSF7 mRNA overexpression were associated with unfavorable clinical outcomes, and the B7-H3 expression was increased gradually in cases with gene amplifications. Moreover, patients with MSI-H had significantly higher PD-L1 or PD-1 expression. Most importantly, in MSI-H group, patients with PD-L1 or PD-1 upregulation had poorer survivals than those with PD-L1/PD-1 downregulation. This is the first study drawing the immune landscapes of the co-stimulator B7 and TNFR families in CRC and showing that MSI-H patients with PD-1/PD-L1 upregulation are associated with poor clinical outcomes, providing potential markers to stratify patients responsive to immune checkpoint therapy.

Immunotherapies targeting programmed cell death protein 1 (PD-1) or its ligand, programmed cell death ligand 1 (PD-L1), dramatically improve the survival of melanoma patients. However, only ∼40% of treated patients demonstrate a clinical response to single-agent anti-PD-1 therapy. An intact tumor response to type-II interferon (i.e. IFN-γ) correlates with response to anti-PD-1, and patients with de novo or acquired resistance may harbor loss-of-function alterations in the JAK/STAT pathway, which lies downstream of the interferon gamma receptor (IFNGR1/2). In this study, we dissected the specific roles of individual JAK/STAT pathway members on the IFN-γ response, and identified JAK1 as the primary mediator of JAK/STAT signaling associated with IFN-γ-induced expression of antigen-presenting molecules MHC-I and MHC-II, as well as PD-L1 and the cytostatic response to IFN-γ. In contrast to the crucial role of JAK1, JAK2 was largely dispensable in mediating most IFN-γ effects. In a mouse melanoma model, inhibition of JAK1/2 in combination with anti-PD-L1 therapy partially blocked anti-tumor immunologic responses, while selective JAK2 inhibition appeared to augment therapy. Amplification of JAK/STAT signaling in tumor cells through genetic inhibition of the negative regulator PTPN2 potentiated IFN-γ response in vitro and in vivo, and may be a target to enhance immunotherapy efficacy.

Checkpoint immunotherapy has revolutionised cancer therapy and is now standard treatment for many malignancies including metastatic melanoma. Acute inflammatory neuropathies, often labelled as Guillain-Barre syndrome, are an uncommon but potentially severe complication of checkpoint immunotherapy with individual cases described but never characterised as a group. We describe a case of acute sensorimotor and autonomic neuropathy following a single dose of combination ipilimumab and nivolumab for metastatic melanoma. A literature search was performed, identifying 14 other cases of acute neuropathy following checkpoint immunotherapy, with the clinical, electrophysiological and laboratory features summarised. Most cases described an acute sensorimotor neuropathy (92%) with hyporeflexia (92%) that could occur from induction up till many weeks after the final dose of therapy. In contrast to Guillain-Barre syndrome, the cerebrospinal fluid (CSF) analysis often shows a lymphocytic picture (50%) and the electrophysiology showed an axonal pattern (55%). Treatment was variable and often in combination. 11 cases received steroid therapy with only 1 death within this group, whereas of the 4 patients who did not receive steroid therapy there were 3 deaths. In conclusion checkpoint immunotherapy – induced acute neuropathies are distinct from and progress differently to Guillain-Barre syndrome. As with other immunotherapy related adverse events corticosteroid therapy should be initiated in addition to usual therapy. [ABSTRACT FROM AUTHOR]

The article announces that James Allison and Tasuku Honjo have received the 2018 Nobel Prize for Medicine.

Peripheral T-cell lymphoma (PTCL) and natural killer/T-cell lymphoma (NKTCL) are rare subtypes of non-Hodgkin's lymphoma that are typically associated with poor treatment outcomes. Contemporary first-line treatment strategies generally involve the use of combination chemoimmunotherapy, radiation and/or stem cell transplant. Salvage options incorporate a number of novel agents including epigenetic therapies (e.g. HDAC inhibitors, DNMT inhibitors) as well as immune checkpoint inhibitors. However, validated biomarkers to select patients for individualized precision therapy are presently lacking, resulting in high treatment failure rates, unnecessary exposure to drug toxicities, and missed treatment opportunities. Recent advances in research on the tumor and microenvironmental factors of PTCL and NKTCL, including alterations in specific molecular features and immune signatures, have improved our understanding of these diseases, though several issues continue to impede progress in clinical translation. In this Review, we summarize the progress and development of the current predictive biomarker landscape, highlight potential knowledge gaps, and discuss the implications on novel therapeutics development in PTCL and NKTCL., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2023 Yap, Lim, Huang, Ong and Chan.)

Tumor-associated tertiary lymphoid structures are ectopic lymphoid aggregates that have considerable morphological, cellular, and molecular similarity to secondary lymphoid organs, particularly lymph nodes. Tumor vessels expressing peripheral node addressin (PNAd) are hallmark features of these structures. Previous work from our laboratory demonstrated that PNAd is displayed on intratumoral vasculature of murine tumors, and its expression is controlled by the engagement of lymphotoxin-α 3 , secreted by effector CD8 T cells, with tumor necrosis factor receptors (TNFR) on tumor endothelial cells (TEC). The goals of the present work were: 1) to identify differences in expression of genes encoding the scaffolding proteins and glycosyl transferases associated with PNAd biosynthesis in TEC and lymph node blood endothelial cells (LN BEC); and 2) to determine which of these PNAd associated components are regulated by TNFR signaling. We found that the same genes encoding scaffolding proteins and glycosyl transferases were upregulated in PNAd + LN BEC and PNAd + TEC relative to their PNAd neg counterparts. The lower level of PNAd expression on TEC vs LN BEC was associated with relatively lower expression of these genes, particularly the carbohydrate sulfotransferase Chst4 . Loss of PNAd on TEC in the absence of TNFR signaling was associated with lack of upregulation of these same genes. A small subset of PNAd + TEC remaining in the absence of TNFR signaling showed normal upregulation of a subset of these genes, but reduced upregulation of genes encoding the scaffolding proteins podocalyxin and nepmucin, and carbohydrate sulfotransferase Chst2. Lastly, we found that checkpoint immunotherapy augmented both the fraction of TEC expressing PNAd and their surface level of this ligand. This work points to strong similarities in the regulation of PNAd expression on TEC by TNFR signaling and on LN BEC by lymphotoxin-β receptor signaling, and provides a platform for the development of novel strategies that manipulate PNAd expression on tumor vasculature as an element of cancer immunotherapy., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 Rodriguez, Parriott and Engelhard.)

Breast cancer is the most common cancer, with the highest mortality rate and the most diagnosed cancer type in women worldwide. To identify the effect innate immune checkpoint for breast cancer immunotherapy, the innate immune prognostic biomarkers were selected through the ICI score model and the risk model in breast cancer patients. Moreover, the reliability and accuracy of the ICI score model and the risk model were further examined through the analysis of breast cancer prognosis and immune cell infiltration. The pan cancer analysis further confirmed and selected CXCL9 as the key innate immune checkpoint for breast cancer immunotherapy and identified three small molecular drugs for target CXCL9 through molecular docking analysis. In summary, CXCL9 significantly correlated with the prognostic of breast cancer and immune cell infiltration and could be innate immune checkpoint for breast cancer immunotherapy. [ABSTRACT FROM AUTHOR]

Interest in host-directed therapies as alternatives/adjuncts to antibiotic treatment has resurged with the increasing prevalence of antibiotic-resistant tuberculosis (TB). Immunotherapies that reinvigorate immune responses by targeting immune checkpoints like PD-1/PD-L1 have proved successful in cancer therapy. Immune cell inhibitory receptors that trigger Mycobacterium tuberculosis-specific immunosuppression, however, are unknown. Here, we show that the levels of CD84, a SLAM family receptor, increase in T and B cells in lung tissues from M. tuberculosis-infected C57BL/6 mice and in peripheral blood mononuclear cells (PBMCs) from pulmonary TB patients. M. tuberculosis challenge experiments using CD84-deficient C57BL/6 mice suggest that CD84 expression likely leads to T and B cell immunosuppression during M. tuberculosis pathogenesis and also plays an inhibitory role in B cell activation. Importantly, CD84-deficient mice showed improved M. tuberculosis clearance and longer survival than M. tuberculosis-infected wild-type (WT) mice. That CD84 is a putative M. tuberculosis infection-specific inhibitory receptor suggests it may be a suitable target for the development of TB-specific checkpoint immunotherapies. IMPORTANCE Immune checkpoint therapies, such as targeting checkpoints like PD-1/PD-L1, have proved successful in cancer therapy and can reinvigorate immune responses. The potential of this approach for treating chronic infectious diseases like TB has been recognized, but a lack of suitable immunotherapeutic targets, i.e., immune cell inhibitory receptors that trigger immunosuppression specifically during Mycobacterium tuberculosis pathogenesis, has limited the application of this strategy in the development of new TB therapies. Our focus in this study was to address this gap and search for an M. tuberculosis-specific checkpoint target. Our results suggest that CD84 is a putative inhibitory receptor that may be a suitable target for the development of TB-specific checkpoint immunotherapies.

Breast cancer is the most common cancer, with the highest mortality rate and the most diagnosed cancer type in women worldwide. To identify the effect innate immune checkpoint for breast cancer immunotherapy, the innate immune prognostic biomarkers were selected through the ICI score model and the risk model in breast cancer patients. Moreover, the reliability and accuracy of the ICI score model and the risk model were further examined through the analysis of breast cancer prognosis and immune cell infiltration. The pan cancer analysis further confirmed and selected CXCL9 as the key innate immune checkpoint for breast cancer immunotherapy and identified three small molecular drugs for target CXCL9 through molecular docking analysis. In summary, CXCL9 significantly correlated with the prognostic of breast cancer and immune cell infiltration and could be innate immune checkpoint for breast cancer immunotherapy.

Background: Malignant gliomas are deadly tumours with few therapeutic options. Although immunotherapy may be a promising therapeutic strategy for treating gliomas, a significant barrier is the CD11b + tumour-associated myeloid cells (TAMCs), a heterogeneous glioma infiltrate comprising up to 40% of a glioma's cellular mass that inhibits anti-tumour T-cell function and promotes tumour progression. A theranostic approach uses a single molecule for targeted radiopharmaceutical therapy (TRT) and diagnostic imaging; however, there are few reports of theranostics targeting the tumour microenvironment., Methods: Utilizing a newly developed bifunctional chelator, Lumi804, an anti-CD11b antibody (αCD11b) was readily labelled with either Zr-89 or Lu-177, yielding functional radiolabelled conjugates for PET, SPECT, and TRT., Findings: 89 Zr/ 177 Lu-labeled Lumi804-αCD11b enabled non-invasive imaging of TAMCs in murine gliomas. Additionally,  177 Lu-Lumi804-αCD11b treatment reduced TAMC populations in the spleen and tumour and improved the efficacy of checkpoint immunotherapy., Interpretation: 89 Zr- and 177 Lu-labeled Lumi804-αCD11b may be a promising theranostic pair for monitoring and reducing TAMCs in gliomas to improve immunotherapy responses., Funding: A full list of funding bodies that contributed to this study can be found in the Acknowledgements section., Competing Interests: Declaration of Competing Interest DM, DST, and JX are employed and own stock options in Lumiphore, Inc. CJA is on the scientific advisory board and has funding from Lumiphore, Inc. GK receives research support from Lumiphore, Inc. All other authors have no conflict of interest in respect to the work presented in this manuscript., (Copyright © 2021 The Authors. Published by Elsevier B.V. All rights reserved.)

PD-1/PD-L1-checkpoint blockade therapy is generally thought to relieve tumor cell-mediated suppression in the tumor microenvironment but PD-L1 is also expressed on non-tumor macrophages and conventional dendritic cells (cDCs). Here we show in mouse tumor models that tumor-draining lymph nodes (TDLNs) are enriched for tumor-specific PD-1+ T cells which closely associate with PD-L1+ cDCs. TDLN-targeted PD-L1-blockade induces enhanced anti-tumor T cell immunity by seeding the tumor site with progenitor-exhausted T cells, resulting in improved tumor control. Moreover, we show that abundant PD-1/PD-L1-interactions in TDLNs of nonmetastatic melanoma patients, but not those in corresponding tumors, associate with early distant disease recurrence. These findings point at a critical role for PD-L1 expression in TDLNs in governing systemic anti-tumor immunity, identifying high-risk patient groups amendable to adjuvant PD-1/PD-L1-blockade therapy. • Tumor-draining lymph nodes (TDLNs) are enriched for tumor-specific PD-1+ T cells • Blocking PD-L1 in TDLNs generates progenitor-exhausted T cells that seed the tumor • PD-L1 blockade on cDCs, not macrophages in TDLNs induces effective tumor immunity • PD-1/PD-L1 interactions in TDLN but not tumor correlate with prognosis in melanoma Dammeijer et al. show that PD-1/PD-L1 interactions occur frequently in tumor-draining lymph nodes (TDLNs) and that specific targeting of PD-L1 in the TDLN induces an effective anti-tumor immune response in multiple mouse models. In addition, PD-1/PD-L1 interactions in TDLNs, but not in tumor, correlate with prognosis in melanoma patients. [ABSTRACT FROM AUTHOR]

Background: Proteins containing the caspase recruitment domain (CARD) play critical roles in cell apoptosis and immunity. However, the impact of CARD genes in tumor immune cell infiltration, responsiveness to checkpoint immunotherapy, and clinical outcomes of gliomas remains unclear. Here, we explore using CARD genes to depict the immune microenvironment and predict the responsiveness of gliomas to anti-PD-1 therapy., Methods: The genome and transcriptome data of 231 patients with isocitrate dehydrogenase wild-type (IDH-wt) gliomas were retrieved from The Cancer Genome Atlas (TCGA) database to screen CARD genes associated with T lymphocyte infiltration in gliomas. Weighted co-expression network and LASSO penalized regression were employed to generate a CARD-associated risk score (CARS). Two independent and publicly available datasets were used to validate the effectiveness of CARS., Results: The CARS divided the 231 glioma patients into high- and low-risk subgroups with distinct immune microenvironment and molecular features. The high-risk group had high CARS and was characterized by enrichment of dysfunctional T lymphocytes in a profound immunosuppressive microenvironment, whereas the low-risk group had low CARS and exhibited an immune exclusion genotype. Moreover, signaling aberrations including upregulation of PI3K/Akt/mTOR, NF-κB, and TGF-β were found in the high-risk group. In contrast, the activated WNT pathway was more evident in the low-risk group. Furthermore, we found that an elevated CARS indicated a decreased overall survival for IDH-wt gliomas under standard care but a clinical benefit from checkpoint immunotherapy., Conclusion: This study developed an immune- and prognosis-relevant risk score, which could be used to enhance our understanding of the heterogeneity of immune microenvironment of gliomas and facilitate to identify patients who will benefit from checkpoint immunotherapy., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2021 Li, Hu, Lin, Zhang, He, Zhong, Wen, Zhang, Jiang, Duan, Guo, Wang, Zeng, Chen, Mou and Sai.)

Immunotherapies have revolutionized cancer treatment. In particular, immune checkpoint therapy (ICT) leads to durable responses in some patients with some cancers. However, the majority of treated patients do not respond. Understanding immune mechanisms that underlie responsiveness to ICT will help identify predictive biomarkers of response and develop treatments to convert non-responding patients to responding ones. ICT primarily acts at the level of adaptive immunity. The specificity of adaptive immune cells, such as T and B cells, is determined by antigen-specific receptors. T cell repertoires can be comprehensively profiled by high-throughput sequencing at the bulk and single-cell level. T cell receptor (TCR) sequencing allows for sensitive tracking of dynamic changes in antigen-specific T cells at the clonal level, giving unprecedented insight into the mechanisms by which ICT alters T cell responses. Here, we review how the repertoire influences response to ICT and conversely how ICT affects repertoire diversity. We will also explore how changes to the repertoire in different anatomical locations can better correlate and perhaps predict treatment outcome. We discuss the advantages and limitations of current metrics used to characterize and represent TCR repertoire diversity. Discovery of predictive biomarkers could lie in novel analysis approaches, such as network analysis of amino acids similarities between TCR sequences. Single-cell sequencing is a breakthrough technology that can link phenotype with specificity, identifying T cell clones that are crucial for successful ICT. The field of immuno-sequencing is rapidly developing and cross-disciplinary efforts are required to maximize the analysis, application, and validation of sequencing data. Unravelling the dynamic behavior of the TCR repertoire during ICT will be highly valuable for tracking and understanding anti-tumor immunity, biomarker discovery, and ultimately for the development of novel strategies to improve patient outcomes., (Copyright © 2020 Kidman, Principe, Watson, Lassmann, Holt, Nowak, Lesterhuis, Lake and Chee.)

Synovial sarcoma (SS) is a soft-tissue malignancy that most often affects patients aged between 15 and 40 years, and the prognosis for patients with metastatic disease is generally poor. This study was performed to evaluate checkpoint blockade immunotherapy markers in SS, including tumor mutational burden (TMB), DNA mismatch repair (MMR) status, and PDL-1 (programmed cell death ligand 1), PD1 (programmed cell death 1), and CD8 expression by normal-tumor paired whole-exome sequencing (WES) and immunohistochemistry (IHC). Outcomes evaluated included event-free and overall survival. Twenty one (21) FISH (Fluorescence In Situ Hybridization)-confirmed SS cases (11 F, 10 M) were studied, with age ranging from 8 to 89 years at diagnosis and follow-up ranging from 1 to 16 years. TMB (n = 16) ranged from 0.83 to 212/Mb (median, 1.7). Only one case showed a high TMB of 212/Mb and missense variants of MMR genes in the primary tumor, while the other 15 cases had a low TMB of less than 5/Mb. IHC was performed on all 21 tumor samples for PD-L1, PD1, CD8, and MMR proteins. PD-L1 membranous staining was detected in 3 of 21 cases (14.3%), ranging from 1 to 5% for tumor proportion score and 1-10 for combined positive score. PD1 was detected in 15 of 21 cases (71.4%), ranging from 1 to 25/HPF (high power field) (median, 2). CD8 stain was seen in all cases, ranging from 2 to 60/HPF (median, 5). PD1 staining results correlated with CD8 staining results (P < 0.0001). No correlation of TMB or IHC markers was found with survival. No fixed pattern of TMB or IHCs between primary and metastatic tumors was observed; there was no correlation between TMB or IHCs and age, location, or diagnosis subtype. All of the cases tested showed retained expression of MMR proteins. The results show that for SS, a tumor with strong driver translocation, most cases have a low TMB, but occasionally a high TMB may be present, as observed in 1 of the 16 (6.25%) cases. The demonstration of a subgroup of SS cases with high TMB might explain the 10% response rate to checkpoint immunotherapy observed in clinical trials in patients with SS., (Copyright © 2020 Elsevier Inc. All rights reserved.)