Clonality of CD4+ Blood T Cells Predicts Longer Survival With CTLA4 or PD-1 Checkpoint Inhibition in Advanced Melanoma

Exploring the potential of the TCR repertoire as a tumor biomarker (Review)

T cells play an important role in adaptive immunity. Mature T cells specifically recognize antigens on major histocompatibility complex molecules through T-cell receptors (TCRs). As the TCR repertoire is highly diverse, its analysis is vital in the assessment of T cells. Advances in sequencing technology have provided convenient methods for further investigation of the TCR repertoire. In the present review, the TCR structure and the mechanisms by which TCRs function in tumor recognition are described. In addition, the potential value of the TCR repertoire in tumor diagnosis is reviewed. Furthermore, the role of the TCR repertoire in tumor immunotherapy is introduced, and the relationships between the TCR repertoire and the effects of different tumor immunotherapies are discussed. Based on the reviewed literature, it may be concluded that the TCR repertoire has the potential to serve as a biomarker for tumor prognosis. However, a wider range of cancer types and more diverse subjects require evaluation in future research to establish the TCR repertoire as a biomarker of tumor immunity.

Preoperative-postoperative immunotherapy as treatment of borderline resectable and oligoprogressive stage III B-D and IV melanoma

INTRODUCTION

Perioperative therapy has gained significant importance in patients with advanced melanoma. Currently, there is little data on the routine use of preoperative immunotherapy in metastatic melanoma outside clinical trials. This study aimed to evaluate the effectiveness of preoperative treatment in patients with borderline resectable stage III or IV melanoma as well as in oligoprogressing stage IV cases; the secondary aim is to describe the safety of surgery after immunotherapy.

MATERIALS AND METHODS

Since 1/Jan/2016 seventeen patients were treated with curative intent neoadjuvant immunotherapy, surgery, and adjuvant immunotherapy, while nineteen patients were operated due to oligoprogression while treted with immunotherapy. Survival was analyzed using the Kaplan-Meier method and association between variables was tested using the chi-squared test.

RESULTS

R0 resection was achieved in 76.5 % of cases after neoadjuvant immunotherapy. 24 % of patients achieved objective RECIST response and 35 % complete or major pathological response. At the median follow-up time of 51.4 months, 64.7 % of patients were free of PD after perioperative treatment, while 3-year RFS and OS rates were 68 % and 80.9 %, respectively. R0 resection was achieved in 73.7 % of oligo-progressing nodules. The median time to PD on immunotherapy after the first oligoprogression was 10.3 months. Immunotherapy did not result in any unexpected surgical complications. No patient died during preoperative treatment due to immunotherapy toxicity or disease progression.

CONCLUSIONS

We confirmed treatment safety and long-term disease control after perioperative immunotherapy. Patients with borderline resectable melanoma should be referred to reference centers using neoadjuvant immunotherapy.

The predictive value of peripheral blood CD4 cells ATP concentration for immune-related adverse events in advanced non-small cell lung cancer patients

OBJECTIVE

Lung cancer with the highest incidence and mortality in the world. Immune checkpoint inhibitors (ICIs), can bring long-term survival benefits to patients, but also can bring immune-related adverse events (irAEs) in some patients during therapy. Therefore, the aim of this study was to investigate the predictive effect of peripheral blood WBC, NLR, sATPCD4 and nATPCD4 on irAEs in advanced non-small cell lung cancer (NSCLC).

METHODS

Clinical data of 112 patients with advanced NSCLC who were treated with PD -1/PD -L1 inhibitor in the Fifth Affiliated Hospital of Guangzhou Medical University from December 15, 2019 to April 30, 2023 were retrospectively analyzed. These patients were divided into the irAEs group (n = 27) and non-irAEs group (n = 85). The clinical data of the two groups were compared. Receiver operating characteristic (ROC) curves were drawn to determine the threshold value of baseline peripheral blood parameters to predict the occurrence of irAEs. Multivariate logistic regression analysis was used to explore the relationship between peripheral blood markers and the incidence of irAEs.

RESULTS

The patient characteristics have no significant difference between irAEs and non-irAEs group. But the baseline peripheral blood WBC, sATPCD4 and nATPCD4 of patients in the irAEs group were higher than those in the non-irAEs group (p < 0.05), and the NLR in irAEs group was similar to in the non-irAEs group (p = 0.639).Univariate analysis showed that high WBC, sATPCD4 and nATPCD4 may the risk factors for the occurrence of irAEs (p < 0.05). Multivariate logistic regression analysis showed that high sATPCD4 and nATPCD4 were independent risk factors for the occurrence of irAEs (p < 0.05). The best critical values of WBC, sATPCD4 and nATPCD4 before treatment for predicting the occurrence of irAEs were 8.165 × 109cells/L (AUC = 0.705) ,484.5 ng/mL (AUC = 0.777), and 156 ng/mL (AUC = 0.840), respectively.

CONCLUSIONS

sATPCD4 and nATPCD4 were independent risk factors for the occurrence of irAEs in advanced NSCLC patients. This discovery provides a new method to predict the occurrence of irAEs in patients. Based on the prediction results, corresponding treatment measures can be taken to reduce the incidence of adverse events.

Toxicity-specific peripheral blood T and B cell dynamics in anti-PD-1 and combined immune checkpoint inhibition

Immune checkpoint inhibitors (ICI) have revolutionized the treatment landscape of advanced malignancies, but come with a diverse spectrum of immune-related adverse events (irAEs). Mechanistic studies can aid the transition from expert-opinion to evidence-based irAE treatment strategies. We aimed to longitudinally characterize peripheral blood T and B cell dynamics in ICI-treated patients by multicolor flow cytometry and serum multiplex immunoassay at baseline, ± 3 weeks and ± 6 weeks or upon clinically relevant irAEs. We analyzed samples from 44 ICI-treated patients (24 anti-PD-1 monotherapy, 20 combined anti-PD-1/anti-CTLA-4; cICI), of whom 21 developed irAEs, and 10 healthy donors. IrAEs after cICI were characterized by significantly enhanced proliferation of Th1-associated, mainly (CD4+) CD27- effector memory T cells, as well as Th17-associated immune responses and germinal center activation (reflected by CXCL13 and IL-21 increases). We observed no changes in CD21lo, memory, class-switched or newly activated B cell subsets. Particularly double-positive PD-1+LAG-3+ CD8+ T cells showed enhanced cytotoxic capacity in patients with irAEs after cICI. Within anti-PD-1 monotherapy, irAEs were associated with modestly enhanced Th1-associated responses reflected by increased serum CXCL9 and CXCL10. In conclusion, ICI-induced toxicity is dominated by enhanced Th1-associated responses, but in cICI we also found evidence for Th17-associated responses and germinal center activation. Together, our data add to the growing body of evidence that irAEs may be driven by newly activated CD4+ helper T cells, specifically after cICI. This study also supports tailored irAE treatment, based on ICI regimen, and to deploy specific strategies such as Th17 inhibition especially in cICI-associated irAEs.

The role of CD4+ T cells in tumor and chronic viral immune responses

Immunotherapies are mainly aimed to promote a CD8+ T cell response rather than a CD4+ T cell response as cytotoxic T lymphocytes (CTLs) can directly kill target cells. Recently, CD4+ T cells have received more attention due to their diverse roles in tumors and chronic viral infections. In antitumor and antichronic viral responses, CD4+ T cells relay help signals through dendritic cells to indirectly regulate CD8+ T cell response, interact with B cells or macrophages to indirectly modulate humoral immunity or macrophage polarization, and inhibit tumor blood vessel formation. Additionally, CD4+ T cells can also exhibit direct cytotoxicity toward target cells. However, regulatory T cells exhibit immunosuppression and CD4+ T cells become exhausted, which promote tumor progression and chronic viral persistence. Finally, we also outline immunotherapies based on CD4+ T cells, including adoptive cell transfer, vaccines, and immune checkpoint blockade. Overall, this review summarizes diverse roles of CD4+ T cells in the antitumor or protumor and chronic viral responses, and also highlights the immunotherapies based on CD4+ T cells, giving a better understanding of their roles in tumors and chronic viral infections.

Novel murine glioblastoma models that reflect the immunotherapy resistance profile of a human disease

BACKGROUND

The lack of murine glioblastoma models that mimic the immunobiology of human disease has impeded basic and translational immunology research. We, therefore, developed murine glioblastoma stem cell lines derived from Nestin-CreERT2QkL/L; Trp53L/L; PtenL/L (QPP) mice driven by clinically relevant genetic mutations common in human glioblastoma. This study aims to determine the immune sensitivities of these QPP lines in immunocompetent hosts and their underlying mechanisms.

METHODS

The differential responsiveness of QPP lines was assessed in the brain and flank in untreated, anti-PD-1, or anti-CTLA-4 treated mice. The impact of genomic landscape on the responsiveness of each tumor was measured through whole exome sequencing. The immune microenvironments of sensitive (QPP7) versus resistant (QPP8) lines were compared in the brain using flow cytometry. Drivers of flank sensitivity versus brain resistance were also measured for QPP8.

RESULTS

QPP lines are syngeneic to C57BL/6J mice and demonstrate varied sensitivities to T cell immune checkpoint blockade ranging from curative responses to complete resistance. Infiltrating tumor immune analysis of QPP8 reveals improved T cell fitness and augmented effector-to-suppressor ratios when implanted subcutaneously (sensitive), which are absent on implantation in the brain (resistant). Upregulation of PD-L1 across the myeloid stroma acts to establish this state of immune privilege in the brain. In contrast, QPP7 responds to checkpoint immunotherapy even in the brain likely resulting from its elevated neoantigen burden.

CONCLUSIONS

These syngeneic QPP models of glioblastoma demonstrate clinically relevant profiles of immunotherapeutic sensitivity and potential utility for both mechanistic discovery and evaluation of immune therapies.

Current Approaches to Neoadjuvant Immunotherapy in Resectable Non-small Cell Lung Cancer

PURPOSE OF REVIEW

For decades, early-stage resectable non-small cell lung cancer (NSCLC), while potentially curable, has been marred by unacceptably high recurrence rates.

RECENT FINDINGS

Anti-PD(L)1 immune checkpoint blockade (ICB) has revolutionized the treatment of advanced NSCLC, and with recent approvals in the peri-operative space, is now poised to transform the systemic treatment paradigm for localized and locally-advanced NSCLC. In this review, we focus on neoadjuvant ICB in resectable NSCLC, highlighting the pre-clinical rationale for neoadjuvant ICB, early clinical trials, randomized phase 3 trial data, and future directions for resectable NSCLC.

Immunologic Predictors for Clinical Responses during Immune Checkpoint Blockade in Patients with Myelodysplastic Syndromes

PURPOSE

The aim of this study is to determine immune-related biomarkers to predict effective antitumor immunity in myelodysplastic syndrome (MDS) during immunotherapy (IMT, αCTLA-4, and/or αPD-1 antibodies) and/or hypomethylating agent (HMA).

EXPERIMENTAL DESIGN

Peripheral blood samples from 55 patients with MDS were assessed for immune subsets, T-cell receptor (TCR) repertoire, mutations in 295 acute myeloid leukemia (AML)/MDS-related genes, and immune-related gene expression profiling before and after the first treatment.

RESULTS

Clinical responders treated with IMT ± HMA but not HMA alone showed a significant expansion of central memory (CM) CD8+ T cells, diverse TCRβ repertoire pretreatment with increased clonality and emergence of novel clones after the initial treatment, and a higher mutation burden pretreatment with subsequent reduction posttreatment. Autophagy, TGFβ, and Th1 differentiation pathways were the most downregulated in nonresponders after treatment, while upregulated in responders. Finally, CTLA-4 but not PD-1 blockade attributed to favorable changes in immune landscape.

CONCLUSIONS

Analysis of tumor-immune landscape in MDS during immunotherapy provides clinical response biomarkers.

Beyond CTLA-4 and PD-1 Inhibition: Novel Immune Checkpoint Molecules for Melanoma Treatment

More than ten years after the approval of ipilimumab, immune checkpoint inhibitors (ICIs) against PD-1 and CTLA-4 have been established as the most effective treatment for locally advanced or metastatic melanoma, achieving durable responses either as monotherapies or in combinatorial regimens. However, a considerable proportion of patients do not respond or experience early relapse, due to multiple parameters that contribute to melanoma resistance. The expression of other immune checkpoints beyond the PD-1 and CTLA-4 molecules remains a major mechanism of immune evasion. The recent approval of anti-LAG-3 ICI, relatlimab, in combination with nivolumab for metastatic disease, has capitalized on the extensive research in the field and has highlighted the potential for further improvement of melanoma prognosis by synergistically blocking additional immune targets with new ICI-doublets, antibody-drug conjugates, or other novel modalities. Herein, we provide a comprehensive overview of presently published immune checkpoint molecules, including LAG-3, TIGIT, TIM-3, VISTA, IDO1/IDO2/TDO, CD27/CD70, CD39/73, HVEM/BTLA/CD160 and B7-H3. Beginning from their immunomodulatory properties as co-inhibitory or co-stimulatory receptors, we present all therapeutic modalities targeting these molecules that have been tested in melanoma treatment either in preclinical or clinical settings. Better understanding of the checkpoint-mediated crosstalk between melanoma and immune effector cells is essential for generating more effective strategies with augmented immune response.

Thymic expression of immune checkpoint molecules and their implication for response to immunotherapies

The thymus is responsible for generating a diverse T cell repertoire that is tolerant to self, but capable of responding to various immunologic insults, including cancer. Checkpoint blockade has changed the face of cancer treatment by targeting inhibitory molecules, which are known to regulate peripheral T cell responses. However, these inhibitory molecules and their ligands are expressed during T cell development in the thymus. In this review, we describe the underappreciated role of checkpoint molecule expression during the formation of the T cell repertoire and detail the importance of inhibitory molecules in regulating T cell lineage commitment. Understanding how these molecules function in the thymus may inform therapeutic strategies for better patient outcomes.

The potential role of the thymus in immunotherapies for acute myeloid leukemia

Understanding the factors which shape T-lymphocyte immunity is critical for the development and application of future immunotherapeutic strategies in treating hematological malignancies. The thymus, a specialized central lymphoid organ, plays important roles in generating a diverse T lymphocyte repertoire during the infantile and juvenile stages of humans. However, age-associated thymic involution and diseases or treatment associated injury result in a decline in its continuous role in the maintenance of T cell-mediated anti-tumor/virus immunity. Acute myeloid leukemia (AML) is an aggressive hematologic malignancy that mainly affects older adults, and the disease's progression is known to consist of an impaired immune surveillance including a reduction in naïve T cell output, a restriction in T cell receptor repertoire, and an increase in frequencies of regulatory T cells. As one of the most successful immunotherapies thus far developed for malignancy, T-cell-based adoptive cell therapies could be essential for the development of a durable effective treatment to eliminate residue leukemic cells (blasts) and prevent AML relapse. Thus, a detailed cellular and molecular landscape of how the adult thymus functions within the context of the AML microenvironment will provide new insights into both the immune-related pathogenesis and the regeneration of a functional immune system against leukemia in AML patients. Herein, we review the available evidence supporting the potential correlation between thymic dysfunction and T-lymphocyte impairment with the ontogeny of AML (II-VI). We then discuss how the thymus could impact current and future therapeutic approaches in AML (VII). Finally, we review various strategies to rejuvenate thymic function to improve the precision and efficacy of cancer immunotherapy (VIII).

Changes in the Immune Cell Repertoire for the Treatment of Malignant Melanoma

Immune checkpoint inhibitors (ICIs) have been used for the treatment of various types of cancers, including malignant melanoma. Mechanistic exploration of tumor immune responses is essential to improve the therapeutic efficacy of ICIs. Since tumor immune responses are based on antigen-specific immune responses, investigators have focused on T cell receptors (TCRs) and have analyzed changes in the TCR repertoire. The proliferation of T cell clones against tumor antigens is detected in patients who respond to treatment with ICIs. The proliferation of these T cell clones is observed within tumors as well as in the peripheral blood. Clonal proliferation has been detected not only in CD8-positive T cells but also in CD4-positive T cells, resident memory T cells, and B cells. Moreover, changes in the repertoire at an early stage of treatment seem to be useful for predicting the therapeutic efficacy of ICIs. Further analyses of the repertoire of immune cells are desirable to improve and predict the therapeutic efficacy of ICIs.

T lymphocyte subsets and PD-1 expression on lymphocytes in peripheral blood of patients with non-small cell lung cancer

The incidence rate and mortality rate of lung cancer (LC) are very high. This study aimed to analyze the T lymphocyte subsets and programmed death-1 (PD-1) expression on lymphocytes in the peripheral blood of non-small cell lung cancer (NSCLC) patients and explore whether there were changes in cellular immunity in NSCLC. Peripheral blood samples were collected from newly diagnosed NSCLC patients and healthy individuals. The T lymphocyte subsets and PD-1 expression were evaluated using flow cytometry. Single-sample gene set enrichment analysis (ssGSEA) was performed to explore the correlations of PD-1 expression with infiltration patterns for tumor-infiltrating T immune cells. By flow cytometry, two populations of lymphocytes in NSCLC patients were observed. Apart from a population of normal volume lymphocytes (Lym1), the other population had larger volume and more particles (Lym2). Compared with the healthy group, the proportion of CD4+ T cells and PD-1 expression on Lym1 was higher, and that of CD8+ T cells was lower in the NSCLC group. In the NSCLC group, the proportions of CD3+ T cells, CD8+ T cells, CD4+CD8+ T (DPT) cells, and PD-1 expression were higher on Lym2 than those on Lym1 (P < .05). ssGSEA showed that tumor infiltrating immune T cells were positively correlated with PD-1 expression. The PD-1 expression on lymphocytes increased in recurrent patients who treated with PD-1 inhibitor. Lym2 may be tumor-infiltrating lymphocytes (TILs) which upregulated PD-1 expression in NSCLC. PD-1 expression on lymphocytes may be used as a recurrence indicator for NSCLC patients treated with PD-1 inhibitors.

Understanding the functional inflammatory factors involved in therapeutic response to immune checkpoint inhibitors for pan-cancer

Immune checkpoint inhibitors (ICIs) fight tumor progression by activating immune conditions. The inflammatory factors are playing a functional role in programmed death-1 (PD-1) or other immune checkpoints. They are involved in regulating the expression of programmed death ligand-1 (PD-L1), the only predictor recognized by the guidelines in response to ICIs. In addition, abundant components of the tumor microenvironment (TME) all interact with various immune factors contributing to the response to ICIs, including infiltration of various immune cells, extracellular matrix, and fibroblasts. Notably, the occurrence of immune-related adverse events (irAEs) in patients receiving ICIs is increasingly observed in sundry organs. IrAEs are often regarded as an inflammatory factor-mediated positive feedback loop associated with better response to ICIs. It deserves attention because inflammatory factors were observed to be different when targeting different immune checkpoints or in the presence of different irAEs. In the present review, we address the research progresses on regulating inflammatory factors for an intentional controlling anti-cancer response with immune checkpoint inhibitors.

Circulating biomarkers of response to immunotherapy and immune-related adverse events

INTRODUCTION

Immune checkpoint blockade has revolutionized cancer treatment. However, response rates vary, and these treatments have a high rate of immune-related side effects, which can be limiting. Thus, tests to predict who will respond and who may experience side effects are of critical importance toward realizing the ultimate goal of precision oncology.

AREAS COVERED

We review several of the most recent advances in circulating biomarkers that have been reported to be useful in predicting response and immune-related adverse events (irAE) to checkpoint blockade immunotherapies (CBI). We focus on high-quality studies published within the last few years. We highlight significant findings, identify areas for improvement, and provide recommendations on how these biomarkers may be translated into clinical utility.

EXPERT OPINION

As newer immunotherapies are developed, there is a pressing need to identify circulating biomarkers that can help predict responses and side effects. Current studies are mostly small-scale and retrospective; there is a need for larger-scale and prospective studies to help validate several of the biomarkers detailed here. As oncology focuses more on precision-based approaches, it is likely that a combination of biomarkers, including circulating ones as detailed here, will have critical utility in guiding clinical decisions.

Evaluation of the TCR Repertoire as a Predictive and Prognostic Biomarker in Cancer: Diversity or Clonality?

Simple Summary

The TCR is the T cell antigen receptor, and it is responsible of the T cell activation, through the HLA-antigen complex recognition. Studying the TCR repertoire in patients with cancer can help to better understand the anti-tumoural responses and it has been suggested to have predictive and or/prognostic values, both for the disease and in response to treatments. The aim of this review is to summarize TCR repertoire studies performed in patients with cancer found in the literature, thoroughly analyse the different factors that can be involved in shaping the TCR repertoire, and draw the current conclusions in this field, especially focusing on whether the TCR diversity—or its opposite, the clonality—can be used as predictors or prognostic biomarkers of the disease.

Abstract

T cells play a vital role in the anti-tumoural response, and the presence of tumour-infiltrating lymphocytes has shown to be directly correlated with a good prognosis in several cancer types. Nevertheless, some patients presenting tumour-infiltrating lymphocytes do not have favourable outcomes. The TCR determines the specificities of T cells, so the analysis of the TCR repertoire has been recently considered to be a potential biomarker for patients’ progression and response to therapies with immune checkpoint inhibitors. The TCR repertoire is one of the multiple elements comprising the immune system and is conditioned by several factors, including tissue type, tumour mutational burden, and patients’ immunogenetics. Its study is crucial to understanding the anti-tumoural response, how to beneficially modulate the immune response with current or new treatments, and how to better predict the prognosis. Here, we present a critical review including essential studies on TCR repertoire conducted in patients with cancer with the aim to draw the current conclusions and try to elucidate whether it is better to encounter higher clonality with few TCRs at higher frequencies, or higher diversity with many different TCRs at lower frequencies.

Changes in T-cell subsets and clonal repertoire during chemoimmunotherapy with pembrolizumab and paclitaxel or capecitabine for metastatic triple-negative breast cancer

BACKGROUND

Chemoimmunotherapy is a standard treatment for triple-negative breast cancer (TNBC), however, the impacts of different chemotherapies on T-cell populations, which could correlate with clinical activity, are not known. Quantifying T-cell populations with flow cytometry and T-cell receptor (TCR) immunosequencing may improve our understanding of how chemoimmunotherapy affects T-cell subsets, and to what extent clonal shifts occur during treatment. TCR immunosequencing of intratumoral T cells may facilitate the identification and monitoring of putatively tumor-reactive T-cell clones within the blood.

METHODS

Blood and tumor biopsies were collected from patients with metastatic TNBC enrolled in a phase Ib clinical trial of first or second-line pembrolizumab with paclitaxel or capecitabine. Using identical biospecimen processing protocols, blood samples from a cohort of patients treated for early-stage breast cancer were obtained for comparison. Treatment-related immunological changes in peripheral blood and intratumoral T cells were characterized using flow cytometry and TCR immunosequencing. Clonal proliferation rates of T cells were compared based on intratumoral enrichment.

RESULTS

When combined with pembrolizumab, paclitaxel and capecitabine resulted in similar time-dependent lymphodepletions across measured peripheral T-cell subsets. Their effects were more modest than that observed following curative-intent dose-dense anthracycline and cyclophosphamide (ddAC) (average fold-change in CD3⁺ cells, capecitabine: -0.42, paclitaxel: -0.56, ddAC: -1.21). No differences in T-cell clonality or richness were observed following capecitabine or paclitaxel-based treatments. Regression modeling identified differences in the emergence of novel T-cell clones that were not detected at baseline (odds compared with ddAC, capecitabine: 0.292, paclitaxel: 0.652). Pembrolizumab with paclitaxel or capecitabine expanded T-cell clones within tumors; however, these clones did not always expand within the blood. Proliferation rates within the blood were similar between clones that were enriched and those that were not enriched within tumors.

CONCLUSION

Chemoimmunotherapy for metastatic TNBC with pembrolizumab and capecitabine or paclitaxel resulted in similar peripheral T-cell subset lymphodepletion without altering T-cell clonal diversity. Regression modeling methods are applicable in immune monitoring studies, such as this to identify the odds of novel T-cell clones emerging during treatment, and proliferation rates of tumor-enriched T-cell clones.

Profiling of immune features to predict immunotherapy efficacy

Immune checkpoint blockade (ICB) therapies exhibit substantial clinical benefit in different cancers, but relatively low response rates in the majority of patients highlight the need to understand mutual relationships among immune features. Here, we reveal overall positive correlations among immune checkpoints and immune cell populations. Clinically, patients benefiting from ICB exhibited increases for both immune stimulatory and inhibitory features after initiation of therapy, suggesting that the activation of the immune microenvironment might serve as the biomarker to predict immune response. As proof-of-concept, we demonstrated that the immune activation score (IS_Δ) based on dynamic alteration of interleukins in patient plasma as early as two cycles (4–6 weeks) after starting immunotherapy can accurately predict immunotherapy efficacy. Our results reveal a systematic landscape of associations among immune features and provide a noninvasive, cost-effective, and time-efficient approach based on dynamic profiling of pre- and on-treatment plasma to predict immunotherapy efficacy.

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Reveal a systematic landscape of associations among immune features in primary, metastatic, and ICB-treated tumors

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The activation of the immune microenvironment might serve as the biomarker of immunotherapy

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Dynamic alteration of interleukins in patient plasma can accurately predict immunotherapy efficacy

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Provide a noninvasive, cost-effective, and time-efficient approach to predict immunotherapy efficacy

Harnessing Antitumor CD4+ T Cells for Cancer Immunotherapy

Simple Summary

Diverse evidence revealed that CD4⁺ T cells play an important role in antitumor immunity by promoting or suppressing cytotoxic T cell responses. This review outlines the role of CD4⁺ T subsets within the tumor microenvironment and summarizes the latest progress regarding their potentials in cancer immunotherapy and methods for improving outcomes in cancer strategies by modulating CD4⁺ T responses.

Abstract

Over the past decades, CD4⁺ T cells have been considered as a supporting actor in the fields of cancer immunotherapy. Until recently, accumulating evidence has demonstrated the critical role of CD4⁺ T cells during antitumor immunity. CD4⁺ T cells can either suppress or promote the antitumor cytotoxic CD8⁺ T cell responses, either in secondary lymphoid organs or in the tumor. In this review, we provide an overview of the multifaceted role of different CD4⁺ T cell subsets in cancer immune response and their contribution during cancer therapies. Specifically, we focus on the latest progress regarding the impact of CD4⁺ T cell modulation on immunotherapies and other cancer therapies and discuss the prospect for harnessing CD4⁺ T cells to control tumor progression and prevent recurrence in patients.

Thymic Function and T-Cell Receptor Repertoire Diversity: Implications for Patient Response to Checkpoint Blockade Immunotherapy

The capacity of T cells to recognize and mount an immune response against tumor antigens depends on the large diversity of the T-cell receptor (TCR) repertoire generated in the thymus during the process of T-cell development. However, this process is dramatically impaired by immunological insults, such as that caused by cytoreductive cancer therapies and infections, and by the physiological decline of thymic function with age. Defective thymic function and a skewed TCR repertoire can have significant clinical consequences. The presence of an adequate pool of T cells capable of recognizing specific tumor antigens is a prerequisite for the success of cancer immunotherapy using checkpoint blockade therapy. However, while this approach has improved the chances of survival of patients with different types of cancer, a large proportion of them do not respond. The limited response rate to checkpoint blockade therapy may be linked to a suboptimal TCR repertoire in cancer patients prior to therapy. Here, we focus on the role of the thymus in shaping the T-cell pool in health and disease, discuss how the TCR repertoire influences patients’ response to checkpoint blockade therapy and highlight approaches able to manipulate thymic function to enhance anti-tumor immunity.

The epigenetic immunomodulator, HBI-8000, enhances the response and reverses resistance to checkpoint inhibitors

Background

Treatment with immune checkpoint inhibitors (ICIs) targeting CTLA-4 and the PD-1/PD-L1 axis is effective against many cancer types. However, due in part to unresponsiveness or acquired resistance, not all patients experience a durable response to ICIs. HBI-8000 is a novel, orally bioavailable class I selective histone deacetylase inhibitor that directly modifies antitumor activity by inducing apoptosis, cell cycle arrest, and resensitization to apoptotic stimuli in adult T cell lymphoma patients. We hypothesized that HBI-8000 functions as an epigenetic immunomodulator to reprogram the tumor microenvironment from immunologically cold (nonresponsive) to hot (responsive).

Method

Mice bearing syngeneic tumors (MC38 and CT26 murine colon carcinoma and A20 B-cell lymphoma were treated daily with HBI-8000 (orally), alone or in combination with PD-1, PD-1 L, or CTLA-4 antibodies. MC38 tumors were also analyzed in nanoString gene expression analysis.

Results

HBI-8000 augmented the activity of ICI antibodies targeting either PD-1, PD-L1 or CTLA-4, and significantly increased tumor regression (p < 0.05) in the above models. Gene expression analysis of the treated MC38 tumors revealed significant changes in mRNA expression of immune checkpoints, with enhanced dendritic cell and antigen-presenting cell functions, and modulation of MHC class I and II molecules.

Conclusions

These findings suggest that HBI-8000 mediates epigenetic modifications in the tumor microenvironment, leading to improved efficacy of ICIs, and provide strong rationale for combination therapies with ICIs and HBI-8000 in the clinical setting.

Precis

As an HDACi, HBI-8000 plays an important role in priming the immune system in the tumor microenvironment. The current preclinical data further justifies testing combination of HBI-8000 and ICIs in the clinic.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12885-021-08702-x.

Effects of RNA methylation N6-methyladenosine regulators on malignant progression and prognosis of melanoma

Background

Melanoma is an extremely aggressive type of skin cancer and experiencing a expeditiously rising mortality in a current year. Exploring new potential prognostic biomarkers and therapeutic targets of melanoma are urgently needed. The ambition of this research was to identify genetic markers and assess prognostic performance of N6-methyladenosine (m6A) regulators in melanoma.

Methods

Gene expression data and corresponding clinical informations of melanoma patients as well as sequence data of normal controls are collected from The Cancer Genome Atlas (TCGA) and the Genotype-Tissue Expression (GTEx) databases. Quantitative real-time PCR (qRT-PCR) analysis was carried out to detect the RNA expression of IGF2BP3 in A375 cell line, melanoma tissues, and normal tissues. Western blot, cell proliferation, and migration assays were performed to assess the ability of IGF2BP3 in A375 cell line.

Results

Differently expressed m6A regulators between tumor samples and normal samples were analyzed. A three-gene prognostic signature including IGF2BP3, RBM15B, and METTL16 was constructed, and the risk score of this signature was identified to be an independent prognostic indicator for melanoma. In addition, IGF2BP3 was verified to promote melanoma cell proliferation and migration in vitro and associate with lymph node metastasis in clinical samples. Moreover, risk score and the expression of IGF2BP3 were positively associated with the infiltrating immune cells and these hub genes made excellent potential drug targets in melanoma.

Conclusion

We identified the genetic changes in m6A regulatory genes and constructed a three-gene risk signature with distinct prognostic value in melanoma. This research provided new insights into the epigenetic understanding of m6A regulators and novel therapeutic strategies in melanoma.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12935-021-02163-9.

Neoantigen Controversies

Next-generation sequencing technologies have revolutionized our ability to catalog the landscape of somatic mutations in tumor genomes. These mutations can sometimes create so-called neoantigens, which allow the immune system to detect and eliminate tumor cells. However, efforts that stimulate the immune system to eliminate tumors based on their molecular differences have had less success than has been hoped for, and there are conflicting reports about the role of neoantigens in the success of this approach. Here we review some of the conflicting evidence in the literature and highlight key aspects of the tumor-immune interface that are emerging as major determinants of whether mutation-derived neoantigens will contribute to an immunotherapy response. Accounting for these factors is expected to improve success rates of future immunotherapy approaches.

Targeting Neoepitopes to Treat Solid Malignancies: Immunosurgery

Successful outcome of immune checkpoint blockade in patients with solid cancers is in part associated with a high tumor mutational burden (TMB) and the recognition of private neoantigens by T-cells. The quality and quantity of target recognition is determined by the repertoire of ‘neoepitope’-specific T-cell receptors (TCRs) in tumor-infiltrating lymphocytes (TIL), or peripheral T-cells. Interferon gamma (IFN-γ), produced by T-cells and other immune cells, is essential for controlling proliferation of transformed cells, induction of apoptosis and enhancing human leukocyte antigen (HLA) expression, thereby increasing immunogenicity of cancer cells. TCR αβ-dependent therapies should account for tumor heterogeneity and availability of the TCR repertoire capable of reacting to neoepitopes and functional HLA pathways. Immunogenic epitopes in the tumor-stroma may also be targeted to achieve tumor-containment by changing the immune-contexture in the tumor microenvironment (TME). Non protein-coding regions of the tumor-cell genome may also contain many aberrantly expressed, non-mutated tumor-associated antigens (TAAs) capable of eliciting productive anti-tumor immune responses. Whole-exome sequencing (WES) and/or RNA sequencing (RNA-Seq) of cancer tissue, combined with several layers of bioinformatic analysis is commonly used to predict possible neoepitopes present in clinical samples. At the ImmunoSurgery Unit of the Champalimaud Centre for the Unknown (CCU), a pipeline combining several tools is used for predicting private mutations from WES and RNA-Seq data followed by the construction of synthetic peptides tailored for immunological response assessment reflecting the patient’s tumor mutations, guided by MHC typing. Subsequent immunoassays allow the detection of differential IFN-γ production patterns associated with (intra-tumoral) spatiotemporal differences in TIL or peripheral T-cells versus TIL. These bioinformatics tools, in addition to histopathological assessment, immunological readouts from functional bioassays and deep T-cell ‘adaptome’ analyses, are expected to advance discovery and development of next-generation personalized precision medicine strategies to improve clinical outcomes in cancer in the context of i) anti-tumor vaccination strategies, ii) gauging mutation-reactive T-cell responses in biological therapies and iii) expansion of tumor-reactive T-cells for the cellular treatment of patients with cancer.

Comprehensive Bioinformatics Analysis Identifies Tumor Microenvironment and Immune-related Genes in Small Cell Lung Cancer

BACKGROUND

Tumor microenvironment (TME) cells play important roles in tumor progression. Accumulating evidence show that they can be exploited to predict the clinical outcomes and therapeutic responses of the tumor. However, the role of immune genes of TME in small cell lung cancer (SCLC) is currently unknown.

OBJECTIVE

To determine the role of immune genes in SCLC.

METHODS

We downloaded the expression profile and clinical follow-up data of SCLC patients from Gene Expression Omnibus (GEO), and TME infiltration profile data of 158 patients using CIBERSORT. The correlation between TME phenotypes, genomic features, and clinicopathological features of SCLC was examined. A gene signature was constructed based on TME genes to further evaluate the relationship between molecular subtypes of SCLC with the prognosis and clinical features.

RESULTS

We identified a group of genes that are highly associated with TME. Several immune cells in TME cells were significantly correlated with SCLC prognosis (p<0.0001). These immune cells displayed diverse immune patterns. Three molecular subtypes of SCLC (TMEC1-3) were identified on the basis of enrichment of immune cell components, and these subtypes showed dissimilar prognosis profiles (p=0.03). The subtype with the best prognosis, TMEC3, was enriched with immune activation factors such as oncogene M0, oncogene M2, T cells follicular helper, and T cells CD8 (p<0.001). The TMEC1 subtype with the worst prognosis was enriched with T cells CD4 naive, B cells memory and Dendritic cells activated cells (p<0.001). Further analysis showed that the TME was significantly enriched with immune checkpoint genes, immune genes, and immune pathway genes (p<0.01). From the gene expression data, we identified four TME-related genes, GZMB, HAVCR2, PRF1 and TBX2, which were significantly associated with poor prognosis in both the training set and the validation set (p<0.05). These genes may serve as markers for monitoring tumor responses to immune checkpoint inhibitors.

CONCLUSION

This study shows that TME features may serve as markers for evaluating the response of SCLC cells to immunotherapy.

Naturally Occurring Genetic Alterations in Proximal TCR Signaling and Implications for Cancer Immunotherapy

T cell-based immunotherapies including genetically engineered T cells, adoptive transfer of tumor-infiltrating lymphocytes, and immune checkpoint blockade highlight the impressive anti-tumor effects of T cells. These successes have provided new hope to many cancer patients with otherwise poor prognoses. However, only a fraction of patients demonstrates durable responses to these forms of therapies and many develop significant immune-mediated toxicity. These heterogeneous clinical responses suggest that underlying nuances in T cell genetics, phenotypes, and activation states likely modulate the therapeutic impact of these approaches. To better characterize known genetic variations that may impact T cell function, we 1) review the function of early T cell receptor-specific signaling mediators, 2) offer a synopsis of known mutations and genetic alterations within the associated molecules, 3) discuss the link between these mutations and human disease and 4) review therapeutic strategies under development or in clinical testing that target each of these molecules for enhancing anti-tumor T cell activity. Finally, we discuss novel engineering approaches that could be designed based on our understanding of the function of these molecules in health and disease.

Immune signature as predictive marker for response to checkpoint inhibitor immunotherapy and overall survival in melanoma

BACKGROUND

Malignant melanoma is an immunogenic skin cancer with an increasing global incidence. Advanced stages of melanoma have poor prognoses. Currently, there are no reliable parameters to predict a patient's response to immune checkpoint inhibitor (ICI) therapy.

METHODS

This study highlights the relevance of a distinct immune signature in the blood for response to ICI therapy and overall survival (OS). Therefore, the immune cell composition in the peripheral blood of 45 melanoma patients prior to ICI therapy was analyzed by flow cytometry and complete blood count.

RESULTS

Responders to ICI therapy displayed an abundance of proliferating CD4+ T cells, an increased lymphocyte-to-monocyte ratio, a low platelet-to-lymphocyte ratio, low levels of CTLA-4+ Treg, and (arginase 1+ ) polymorphonuclear myeloid-derived suppressor cells (PMN-MDSC). Nevertheless, non-responders with similar immune cell compositions also benefited from therapy displaying increased long-term OS.

CONCLUSIONS

Our study demonstrated that the observed immune signature in the peripheral blood of melanoma patients prior to treatment could identify responders as well as non-responders that benefit from ICI immunotherapies.

The effect of pretreatment BMI on the prognosis and serum immune cells in advanced LSCC patients who received ICI therapy

This study aims to evaluate the prognosis and serum immune cells of patients with different pretreatment body mass index (BMI) values. The data of 61 newly diagnosed patients with advanced lung squamous cell carcinoma (LSCC) who received immune checkpoint inhibitors (ICIs) combined with chemotherapy were obtained from the database of Rizhao People's Hospital (Rizhao, Shandong). According to the cutoff value of BMI (23.2 kg/m2), 32 patients had a high BMI and the remaining 29 patients had a low BMI. The effects of different BMIs on the prognosis and serum immune cells of patients were analyzed. The median progression-free survival (PFS) times were 7.72 months in the high BMI group and 4.83 months in the low BMI group [adjusted hazard ratio (HR), 0.23; 95% confidence interval (CI), 0.11-0.48; P < .001]. In terms of the overall survival (OS), the median times of the high BMI group and low BMI group were 18.10 and 13.90 months, respectively (adjusted HR, 0.15; 95% CI, 0.07-0.32; P < .001). After 4 cycles of ICI therapy combined with chemotherapy, the objective response rate was 59.4% for the high BMI group and 20.7% for the low BMI group (P = .002). In addition, the number of serum immune cells in patients with high BMI was significantly higher than that in patients with low BMI (all P < .001). There was a linear relationship between BMI value and the number of serum immune cells (all R2 > 0.7). The current results showed that high BMI is associated with better prognosis in LSCC patients who received ICIs, which may be related to higher levels of serum immune cells.

Emerging dynamics pathways of response and resistance to PD-1 and CTLA-4 blockade: tackling uncertainty by confronting complexity

Immune checkpoint inhibitors provide considerable therapeutic benefit in a range of solid cancers as well as in a subgroup of hematological malignancies. Response rates are however suboptimal, and despite considerable efforts, predicting response to immune checkpoint inhibitors ahead of their administration in a given patient remains elusive. The study of the dynamics of the immune system and of the tumor under immune checkpoint blockade brought insight into the mechanisms of action of these therapeutic agents. Equally relevant are the mechanisms of adaptive resistance to immune checkpoint inhibitors that have been uncovered through this approach. In this review, we discuss the dynamics of the immune system and of the tumor under immune checkpoint blockade emanating from recent studies on animal models and humans. We will focus on mechanisms of action and of resistance conveying information predictive of therapeutic response.

Emerging Role of T-cell Receptor Constant β Chain-1 (TRBC1) Expression in the Flow Cytometric Diagnosis of T-cell Malignancies

T-cell clonality testing is integral to the diagnostic work-up of T-cell malignancies; however, current methods lack specificity and sensitivity, which can make the diagnostic process difficult. The recent discovery of a monoclonal antibody (mAb) specific for human TRBC1 will greatly improve the outlook for T-cell malignancy diagnostics. The anti-TRBC1 mAb can be used in flow cytometry immunophenotyping assays to provide a low-cost, robust, and highly specific test that detects clonality of immunophenotypically distinct T-cell populations. Recent studies demonstrate the clinical utility of this approach in several contexts; use of this antibody in appropriately designed flow cytometry panels improves detection of circulating disease in patients with cutaneous T-cell lymphoma, eliminates the need for molecular clonality testing in the context of large granular lymphocyte leukemia, and provides more conclusive results in the context of many other T-cell disorders. It is worth noting that the increased ability to detect discrete clonal T-cell populations means that identification of T-cell clones of uncertain clinical significance (T-CUS) will become more common. This review discusses this new antibody and describes how it defines clonal T-cells. We present and discuss assay design and summarize findings to date about the use of flow cytometry TRBC1 analysis in the field of diagnostics, including lymph node and fluid sample investigations. We also make suggestions about how to apply the assay results in clinical work-ups, including how to interpret and report findings of T-CUS. Finally, we highlight areas that we think will benefit from further research.

CD4+ T Cells: Multitasking Cells in the Duty of Cancer Immunotherapy

Cancer immunotherapy activates the immune system to specifically target malignant cells. Research has often focused on CD8+ cytotoxic T cells, as those have the capacity to eliminate tumor cells after specific recognition upon TCR-MHC class I interaction. However, CD4+ T cells have gained attention in the field, as they are not only essential to promote help to CD8+ T cells, but are also able to kill tumor cells directly (via MHC-class II dependent recognition) or indirectly (e.g., via the activation of other immune cells like macrophages). Therefore, immunotherapy approaches have shifted from only stimulating CD8+ T cells to targeting and assessing both, CD4+ and CD8+ T cell subsets. Here, we discuss the various subsets of CD4+ T cells, their plasticity and functionality, their relevance in the antitumor immune response in patients affected by cancer, and their ever-growing role in therapeutic approaches for human cancer.

Distinct Immunophenotypes of T Cells in Bronchoalveolar Lavage Fluid From Leukemia Patients With Immune Checkpoint Inhibitors-Related Pulmonary Complications

Patients with acute myeloid leukemia (AML) and myelodysplastic syndrome (MDS) treated with immune checkpoint inhibitors (ICIs) are at risk of pneumonitis as well as pneumonia (combined henceforth as ICI-related pulmonary complications). Little is known about the cellular and molecular mechanisms underlying ICI-related pulmonary complications. We characterized lymphocytes from bronchoalveolar lavage (BAL) fluid and peripheral blood from seven AML/MDS patients with pulmonary symptoms after ICI-based therapy (ICI group) and four ICI-naïve AML/MDS patients with extracellular bacterial or fungal pneumonias (controls). BAL T cells in the ICI group were clonally expanded, and BAL IFNγ⁺ IL-17^- CD8⁺ T and CXCR3⁺ CCR6⁺ Th17/Th1 cells were enriched in the ICI group. Our data suggest that these cells may play a critical role in the pathophysiology of ICI-related pulmonary complications. Understanding of these cell populations may also provide predictive and diagnostic biomarkers of ICI-related pulmonary complications, eventually enabling differentiation of pneumonitis from pneumonia in AML/MDS patients receiving ICI-based therapies.

Neoadjuvant Immunotherapy for High-Risk, Resectable Malignancies: Scientific Rationale and Clinical Challenges

Neoadjuvant immunotherapy involves administering immune checkpoint inhibitors before surgical resection in high-risk resectable disease. This strategy was shown to have a high pathological response rate and prolonged relapse-free survival in randomized trials in melanoma, glioblastoma, and colon cancer with small numbers of patients. In resectable cancers, immune checkpoint inhibitors such as anti-programmed cell death-1 (PD1) and anti-cytotoxic T-lymphocyte-associated protein-4 (CTLA-4) can enhance antitumor immunity by activating antigen-specific T cells found in the primary tumor. These tumor-reactive T cells continue to exert antitumor effects on remaining neoplastic cells after the resection of the primary tumor, potentially preventing relapses from occurring. Based on the scientific rationale and early clinical observations with surrogate survival endpoints, neoadjuvant immunotherapy may provide an effective alternative to other therapeutic strategies such as adjuvant treatment. However, this can be determined only by conducting randomized controlled trials comparing neoadjuvant immunotherapy with the current standard of care for each tumor site. This review discusses the cellular mechanisms that occur during successful neoadjuvant immunotherapy and highlights the clinical data from the available human studies that support the preclinical mechanistic data. Here we also discuss strategies required for successful neoadjuvant immunotherapy, including combination treatment strategies and resistance mechanisms to neoadjuvant treatment.

Long-Term Outcomes of a Phase I Study With UV1, a Second Generation Telomerase Based Vaccine, in Patients With Advanced Non-Small Cell Lung Cancer

Human telomerase reverse transcriptase (hTERT) is a target antigen for cancer immunotherapy in patients with non-small cell lung cancer (NSCLC). We have tested a novel hTERT vaccine, UV1, designed to give high population coverage. UV1 is composed of three synthetic long peptides containing multiple epitopes identified by epitope spreading data from long-term survivors from previous hTERT vaccination trials. Eighteen non-HLA-typed patients with stage III/IV NSCLC with no evidence of progression after prior treatments, were enrolled in a phase I dose-escalation study of UV1 vaccination with GM-CSF as adjuvant, evaluating safety, immune response, and long-term clinical outcome. Treatment with UV1 was well tolerated with no serious adverse events observed. Seventeen patients were evaluable for tumor response; 15 patients had stable disease as best response. The median progression free survival (PFS) was 10.7 months, and the median overall survival (OS) was 28.2 months. The OS at 4 years was 39% (7/18). Five patients are alive (median survival 5.6 years), and none of these are known to have received checkpoint therapy after vaccination. UV1 induced specific T-cell responses in the majority (67%) of patients. Immune responses were dynamic and long lasting. Both immune response (IR) and OS were dose related. More patients in the highest UV1 dosage group (700 μg) developed IRs compared to the other groups, and the IRs were stronger and occurred earlier. Patients in this group had a 4-year OS of 83%. The safety and clinical outcome data favor 700 μg as the preferred UV1 dose in this patient population. These results provide a rationale for further clinical studies in NSCLC with UV1 vaccination in combination with immune checkpoint blockade.

Clinical Trial Registration

https://www.clinicaltrials.gov, identifier NCT0178909.

Immune Checkpoint Inhibitors for the Treatment of Cancer: Clinical Impact and Mechanisms of Response and Resistance

Immune checkpoint inhibitors (ICIs) have made an indelible mark in the field of cancer immunotherapy. Starting with the approval of anti-cytotoxic T lymphocyte-associated protein 4 (anti-CTLA-4) for advanced-stage melanoma in 2011, ICIs-which now also include antibodies against programmed cell death 1 (PD-1) and its ligand (PD-L1)-quickly gained US Food and Drug Administration approval for the treatment of a wide array of cancer types, demonstrating unprecedented extension of patient survival. However, despite the success of ICIs, resistance to these agents restricts the number of patients able to achieve durable responses, and immune-related adverse events complicate treatment. Thus, a better understanding of the requirements for an effective and safe antitumor immune response following ICI therapy is needed. Studies of both tumoral and systemic changes in the immune system following ICI therapy have yielded insight into the basis for both efficacy and resistance. Ultimately, by building on these insights, researchers should be able to combine ICIs with other agents, or design new immunotherapies, to achieve broader and more durable efficacy as well as greater safety. Here, we review the history and clinical utility of ICIs, the mechanisms of resistance to therapy, and local and systemic immune cell changes associated with outcome.

T cell regeneration after immunological injury

Following periods of haematopoietic cell stress, such as after chemotherapy, radiotherapy, infection and transplantation, patient outcomes are linked to the degree of immune reconstitution, specifically of T cells. Delayed or defective recovery of the T cell pool has significant clinical consequences, including prolonged immunosuppression, poor vaccine responses and increased risks of infections and malignancies. Thus, strategies that restore thymic function and enhance T cell reconstitution can provide considerable benefit to individuals whose immune system has been decimated in various settings. In this Review, we focus on the causes and consequences of impaired adaptive immunity and discuss therapeutic strategies that can recover immune function, with a particular emphasis on approaches that can promote a diverse repertoire of T cells through de novo T cell formation.

Telomerase and CD4 T Cell Immunity in Cancer

Telomerase reverse transcriptase (TERT) is a conserved self-tumor antigen which is overexpressed in most tumors and plays a critical role in tumor formation and progression. As such, TERT is an antigen of great relevance to develop widely applicable immunotherapies. CD4 T cells play a major role in the anti-cancer response alone or with other effector cells such as CD8 T cells and NK cells. To date, efforts have been made to identify TERT peptides capable of stimulating CD4 T cells that are also able to bind diverse MHC-II alleles to ease immune status monitoring and immunotherapies. Here, we review the current status of TERT biology, TERT/MHC-II immunobiology, and past and current vaccine clinical trials. We propose that monitoring CD4 T cell immunity against TERT is a simple and direct way to assess immune surveillance in cancer patients and a new way to predict the response to immune checkpoint inhibitors (ICPi). Finally, we present the initial results of a systematic discovery of TERT peptides able to bind the most common HLA Class II alleles worldwide and show that the repertoire of MHC-II TERT peptides is wider than currently appreciated.

Liquid biopsy and tumor heterogeneity in metastatic solid tumors: the potentiality of blood samples

In a large number of cancer types, treatment selection depends on the presence of specific tumor biomarkers. Due to the dynamic nature of cancer, very often these predictive biomarkers are not uniformly present in all cancer cells. Tumor heterogeneity represents indeed one of the main causes of therapeutic failure, and its decoding remains a major ongoing challenge in the field.

Liquid biopsy is the sampling and analysis of non-solid biological tissue often through rapid and non-invasive methods, which allows the assessment in real-time of the evolving landscape of cancer. Samples can be obtained from blood and most other bodily fluids. A blood-based liquid biopsy can capture circulating tumor cells and leukocytes, as well as circulating tumor-derived nucleic acids.

In this review, we discuss the current and possibly future applications of blood-based liquid biopsy in oncology, its advantages and its limitations in clinical practice. We specifically focused on its role as a tool to capture tumor heterogeneity in metastatic cancer patients.

Precision Medicine for NSCLC in the Era of Immunotherapy: New Biomarkers to Select the Most Suitable Treatment or the Most Suitable Patient

In recent years, the evolution of treatments has made it possible to significantly improve the outcomes of patients with non-small cell lung cancer (NSCLC). In particular, while molecular targeted therapies are effective in specific patient sub-groups, immune checkpoint inhibitors (ICIs) have greatly influenced the outcomes of a large proportion of NSCLC patients. While nivolumab activity was initially assessed irrespective of predictive biomarkers, subsequent pivotal studies involving other PD-1/PD-L1 inhibitors in pre-treated advanced NSCLC (atezolizumab within the OAK study and pembrolizumab in the Keynote 010 study) reported the first correlations between clinical outcomes and PD-L1 expression. However, PD-L1 could not be sufficient on its own to select patients who may benefit from immunotherapy. Many studies have tried to discover more precise markers that are derived from tumor tissue or from peripheral blood. This review aims to analyze any characteristics of the immunogram that could be used as a predictive biomarker for response to ICIs. Furthermore, we describe the most important genetic alteration that might predict the activity of immunotherapy.

Targeted therapy and immunotherapy: Emerging biomarkers in metastatic melanoma

Targeted therapy directed against oncogenic BRAF mutations and immune checkpoint inhibitors have transformed melanoma therapy over the past decade and prominently improved patient outcomes. However, not all patients will respond to targeted therapy or immunotherapy and many relapse after initially responding to treatment. This unmet need presents two major challenges. First, can we elucidate novel oncogenic drivers to provide new therapeutic targets? Second, can we identify patients who are most likely to respond to current therapeutic strategies in order to both more accurately select populations and avoid undue drug exposure in patients unlikely to respond? In an effort to evaluate the current state of the field with respect to these questions, we provide an overview of some common oncogenic mutations in patients with metastatic melanoma and ongoing efforts to therapeutically target these populations, as well as a discussion of biomarkers for response to immune checkpoint inhibitors-including tumor programmed death ligand 1 expression and the future use of neoantigens as a means of truly personalized therapy. This information is becoming important in treatment decision making and provides the framework for a treatment algorithm based on the current landscape in metastatic melanoma.

Immune-related adverse events of checkpoint inhibitors: Insights into immunological dysregulation

Immune checkpoint inhibitors (ICIs) targeting against programmed cell death-1(PD-1) and cytotoxic T-lymphocyte antigen-4 (CTLA-4) have shown efficacy in cancer treatment. However, a spectrum of immune-related adverse events (irAEs) have raised concerns about their clinical application. IrAEs are distinct from traditional chemo- and radiotherapy-induced toxicities, as they are related in particular to the dysregulation of immune system and autoimmunity. The underlying pathogenesis of irAEs remains elusive. Understanding of the potential underlying mechanism is of great importance for the management of irAEs and the development of new ICIs with insignificant irAEs. In this review, we summarize the current evidence to provide insights into the biological basis of irAEs and provide a potential explanation for their pathogenesis, with focus on the relationship between checkpoint molecules and immune cell regulation.

Pegylated recombinant human granulocyte colony-stimulating factor regulates the immune status of patients with small cell lung cancer

BACKGROUND

Small cell lung cancer (SCLC) is an aggressive disease involving immunodeficiency for which chemotherapy is the standard treatment. Pegylated recombinant human granulocyte colony-stimulating factor (PEG-rhG-CSF) is widely used for primary or secondary prophylaxis of febrile neutropenia (FN) in chemotherapy. However, whether PEG-rhG-CSF influences immune cells, such as lymphocytes, remains unclear.

METHODS

A total of 17 treatment-naïve SCLC patients were prospectively enrolled and divided into the PEG-rhG-CSF and control groups according to their FN risk. Longitudinal sampling of peripheral blood was performed before, after and 4-6 days after the first cycle of chemotherapy. Flow cytometry was used to assess lymphocyte subsets, including CD3⁺ T, CD4⁺ T, CD8⁺ T, NK, and B cells. The diversity and clonality of the T-cell receptor (TCR) repertoire was analyzed by next-generation sequencing.

RESULTS

In the PEG-rhG-CSF group, the proportions of CD3⁺ T and CD4⁺ T cells had increased significantly (P = 0.002, P = 0.020, respectively), whereas there was no increase in CD8⁺ T cells. Further, TCR diversity increased (P = 0.009) and clonality decreased (P = 0.004) significantly after PEG-rhG-CSF treatment. However, these factors showed opposite trends before and after chemotherapy. Vβ and Jβ gene fragment types, which determine TCR diversity, were significantly amplified in the PEG-rhG-CSF group. The change in TCR diversity was significantly correlated with changes in the CD3⁺ T or CD4⁺ T cell proportions, but not the CD8⁺ T cell proportion.

CONCLUSIONS

PEG-rhG-CSF regulates the immune status of SCLC patients; CD4⁺ T cells may be the main effector cells involved in this process. These findings may optimize the treatment of SCLC.

KEY POINTS

PEG-rhG-CSF regulates SCLC immunity. PEG-rhG-CSF increased CD3⁺ T and CD4⁺ T cell proportions. PEG-rhG-CSF increased TCR diversity and decreased clonality in peripheral blood. Change in TCR diversity were correlated with CD3⁺ T or CD4⁺ T changes.

T-cell receptor diversity as a prognostic biomarker in melanoma patients

There is increasing evidence that T-cell receptor (TCR) repertoire diversity can be a predictive biomarker of immune responses in cancer patients. However, the characteristics of the T-cell repertoire together with its prognostic significance in melanoma patients and impact on disease progression remain unknown. We investigated the combinatorial TCR repertoire diversity by semi-quantitative multi-N-plex PCR in peripheral blood samples from 44 melanoma patients together with seven matched metastatic lymph nodes and explored its potential predictive value on clinical prognosis. The diversity was quantified by calculating both richness (number of different specificities) and evenness (relative abundance of the different specificities). Our results revealed that a higher TCR repertoire diversity in blood of patients was associated with a longer PFS, while divpenia (low repertoire diversity) was linked with poor prognosis. The diversity was significantly higher in patients undergoing late relapse and long survival compared to patients who progressed rapidly. Interestingly, the TCR repertoire diversity in tumor may have a potential prognostic value. Thus, our study highlights that the TCR repertoire diversity is a prognostic indicator of clinical outcome in patients with melanoma.

Immunopathogenesis of Immune Checkpoint Inhibitor-Related Adverse Events: Roles of the Intestinal Microbiome and Th17 Cells

The advent of novel, innovative, and effective anti-cancer immunotherapies has engendered an era of renewed optimism among cancer specialists and their patients. Foremost among these successful immunotherapies are monoclonal antibodies (MAbs) which target immune checkpoint inhibitor (ICI) molecules, most prominently cytotoxic T-lymphocyte-associated protein (CTLA-4) and programmed cell death protein-1 (PD-1) and its major ligand, PD-L1. These immunotherapeutic agents are, however, often associated with the occurrence of immune-mediated toxicities known as immune-related adverse events (IRAEs). The incidence of severe toxicities increases substantially when these agents are used together, particularly with CTLA-4 in combination with PD-1 or PD-L1 antagonists. Accordingly, dissociating the beneficial anti-tumor therapeutic activity of these agents from the emergence of IRAEs represents a significant challenge to attaining the optimum efficacy of ICI-targeted immunotherapy of cancer. This situation is compounded by an increasing awareness, possibly unsurprising, that both the beneficial and harmful effects of ICI-targeted therapies appear to result from an over-reactive immune system. Nevertheless, this challenge may not be insurmountable. This contention is based on acquisition of recent insights into the role of the gut microbiome and its products as determinants of the efficacy of ICI-targeted immunotherapy, as well as an increasing realization of the enigmatic involvement of Th17 cells in both anti-tumor activity and the pathogenesis of some types of IRAEs. Evidence linking the beneficial and harmful activities of ICI-targeted immunotherapy, recent mechanistic insights focusing on the gut microbiome and Th17 cells, as well as strategies to attenuate IRAEs in the setting of retention of therapeutic activity, therefore represent the major thrusts of this review.