A new role for circulating T follicular helper cells in humoral response to anti-PD-1 therapy

Tertiary lymphoid structures as a biomarker in immunotherapy and beyond: Advancing towards clinical application

Tertiary lymphoid structures (TLSs) are ectopic immune cell clusters formed in nonlymphoid tissues affected by persistent inflammation, such as in cancer and prolonged infections. They have features of the structure and function of secondary lymphoid organs, featuring central CD20+ B cells, surrounded by CD3+ T cells, CD21+ follicular dendritic cells, and CD68+ macrophages, with a complex vascular system. TLS formation is governed by lymphotoxin-α1β2, TNF, and chemokines like CCL19, CCL21, and CXCL13, differing from secondary lymphoid organ development in developing later in life at sites of chronic inflammation. Their role in enhancing immune responses, particularly in the context of cancer, makes them a focal point in immunotherapy. This review discusses recent advances in TLS assessment that involves complex gene expression signatures, histological analysis, artificial intelligence, and spatial omics. The presence and maturity of TLS are associated with better outcomes in various cancers, acting as a biomarker for immunotherapy effectiveness. This review explores the structure, formation, and role of TLS in disease prognosis, including their roles in immunotherapy and non-immunotherapy treatments, highlighting a need to develop novel techniques for precise characterization of TLS as well as their significance as predictive biomarkers beyond traditional biomarkers.

Multifaceted function of B cells in tumorigenesis

B lymphocytes (B cells) play a complex and paradoxical role in tumorigenesis. They can recognize tumor-associated antigens, present these antigens to T cells, and produce antibodies that directly target and eliminate tumor cells. This makes B cells a potentially powerful ally in combating cancer. However, B cells also exhibit immunosuppressive functions, secreting cytokines like IL-10 or generating tumor-promoting antibodies that dampen the anti-tumor immune response, and some tumor cells have even been shown to exploit B cells to promote their growth and metastasis. This dual nature of B cells presents both opportunities and challenges for tumor immunotherapy. In this review, we summarize the mechanisms underlying the multifaceted functions of B cells and their current applications in cancer immunotherapy. Furthermore, we also explore the key issues and future directions in this field, emphasizing the need for further research to fully harness the anti-tumor potential of B cells in the fight against cancer.

Myeloid Cells Induce Infiltration and Activation of B Cells and CD4+ T Follicular Helper Cells to Sensitize Brain Metastases to Combination Immunotherapy

Brain metastasis is a poor prognostic factor in patients with cancer. Despite showing efficacy in many extracranial tumors, immunotherapy with anti-PD-1 mAb or anti-CTLA4 mAb seems to be less effective against intracranial tumors. Promisingly, recent clinical studies have reported that combination therapy with anti-PD-1 and anti-CTLA4 mAbs has a potent antitumor effect on brain metastasis, highlighting the need to elucidate the detailed mechanisms controlling the intracranial tumor microenvironment (TME) to develop effective immunotherapeutic strategies. In this study, we analyzed the tumor-infiltrating lymphocytes in murine models of brain metastasis that responded to anti-CTLA4 and anti-PD-1 mAbs. Activated CD4+ T follicular helper (TFH) cells with high CTLA4 expression characteristically infiltrated the intracranial TME, which were activated by combination anti-CTLA4 and anti-PD-1 treatment. The loss of TFH cells suppressed the additive effect of CTLA4 blockade on anti-PD-1 mAb. B-cell-activating factor belonging to the TNF family (BAFF) and a proliferation-inducing ligand (APRIL) produced by abundant myeloid cells, particularly CD80hiCD206lo proinflammatory M1-like macrophages, in the intracranial TME induced B-cell and TFH-cell infiltration and activation. Furthermore, the intracranial TME of patients with non-small cell lung cancer featured TFH- and B-cell infiltration as tertiary lymphoid structures. Together, these findings provide insights into the immune cell cross-talk in the intracranial TME that facilitates an additive antitumor effect of CTLA4 blockade with anti-PD-1 treatment, supporting the potential of a combination immunotherapeutic strategy for brain metastases. Significance: B-cell and CD4+ T follicular helper cell activation via BAFF/APRIL from abundant myeloid cells in the intracranial tumor microenvironment enables a combinatorial effect of CTLA4 and PD-1 blockade in brain metastases.

RNA modification writer-based immunological profile and genomic landscape of tumor microenvironment in lung adenocarcinoma

BACKGROUND

Recent studies have highlighted the role of RNA modification, that is, the dysregulation of epitranscriptomics, in tumorigenesis and progression. The potential for undoing epigenetic changes may develop novel therapeutic and prognostic approaches. However, the roles of these RNA modifications in the tumor microenvironment (TME) are still unknown.

METHODS

We assessed the expression properties and genetic alterations of 26 RNA modification writers, including adenosine-to-inosine RNA editing, alternative polyadenylation, m1A, and m6A in 502 lung adenocarcinoma (LUAD) samples from the Cancer Genome Atlas (TCGA) datasets. Then, we used differentially expressed gene (DEGs) to develop a signature for predicting patient outcomes, which was dubbed the "writer score" for RNA-modified writers. In addition, we analyzed the association between TME features, molecular subtypes, treatment sensitivity, and immunotherapy efficacy.

RESULTS

We comprehensively evaluated the changes in multilayer RNA modification writers and identified the role of RNA modification writer expression imbalances in LUAD emergence and progression. Additionally, we constructed a risk-score model based on six LUAD prognosis-associated differentially expressed RNA modification writer genes. Kaplan-Meier (K-M) analyses revealed that the low risk-score signature had high overall patient survival. The predictive significance of the risk-score model was demonstrated using both univariate and multivariate Cox analyses. The risk-score model was positively correlated with the immune- and proliferation-related pathways. In response to anti-cancer treatment, high-risk score is related with high TMB, which has been discovered to correlate with immunotherapy effectiveness.

CONCLUSION

This study showed a strong correlation between the TME variety, level of complexity, and the four types of RNA modification writers. In addition, this scoring system could potentially predict effective immunotherapy and deepens our understanding of TME characteristics.

PD-1 suppresses human CD38+ circulating Tfr cells and regulates humoral immunity

BACKGROUND

Anti-programmed cell death protein 1 (anti-PD-1) antibodies have achieved revolutionary success in cancer therapy. However, the impact of anti-PD-1 therapy on host humoral immunity in humans during cancer immunotherapy requires further investigation.

METHODS

We evaluated immunoglobulin titers by ELISA and screened the immune landscape of immune cells from 25 healthy donors and 50 cases including 25 new-onset hepatocellular carcinoma (HCC) patients prior to systemic treatment and 25 HCC patients undergoing anti-PD-1 therapy by multicolor flow cytometry. Flow or beads sorted cells were cultured ex vivo for proliferation and functional analysis.

RESULTS

Anti-PD-1 therapy significantly increased the levels of IgG and IgA in the periphery of HCC patients. Anti-PD-1 treatment led to an increase in plasmablasts and a notable rise in circulating T follicular regulatory (cTfr) cells, while changes in circulating B cells, T follicular helper cells, or regulatory T cells were not significant. Anti-PD-1 therapy also influenced the proliferation and function of cTfr cells, promoting the differentiation of CD38+ cTfr cells. We observed that the CD38+ Tfr cell subset in the peripheral blood can promote plasmablast differentiation, associated with altered antibody production.

CONCLUSIONS

Together, these data demonstrate the immunomodulatory role of PD-1 in restricting the differentiation and function of human cTfr cells and in regulating humoral immunity.

Role of tertiary lymphoid structures and B cells in clinical immunotherapy of gastric cancer

Gastric cancer is a common malignant tumor of the digestive tract, and its treatment remains a significant challenge. In recent years, the role of various immune cells in the tumor microenvironment in cancer progression and treatment has gained increasing attention. Immunotherapy, primarily based on immune checkpoint inhibitors, has notably improved the prognosis of patients with gastric cancer; however, challenges regarding therapeutic efficacy persist. Histological features within the tumor microenvironment, such as tertiary lymphoid structures (TLSs), tumor-infiltrating lymphocytes, and the proportion of intratumoral stroma, are emerging as potentially effective prognostic factors. In gastric cancer, TLSs may serve as local immune hubs, enhancing the ability of immune cells to interact with and recognize tumor antigens, which is closely linked to the effectiveness of immunotherapy and improved survival rates in patients. However, the specific cell type driving TLS formation in tumors has not yet been elucidated. Mature TLSs are B-cell regions containing germinal centers. During germinal center formation, B cells undergo transformations to become mature cells with immune function, exerting anti-tumor effects. Therefore, targeting B cells within TLSs could provide new avenues for gastric cancer immunotherapy. This review, combined with current research on TLSs and B cells in gastric cancer, elaborates on the relationship between TLSs and B cells in the prognosis and immunotherapy of patients with gastric cancer, aiming to provide effective guidance for precise immunotherapy.

IRF4: A potential prognostic biomarker for immunotherapy in NSCLC

BACKGROUND

Immunotherapy is revolutionizing the management of advanced non-small cell lung cancer (NSCLC). However, sustained responses are observed in only a minority of patients. Reliable biomarkers are required to identify potential beneficiaries. Interferon regulatory factor 4 (IRF4) plays a crucial role in immune regulation, suggesting its potential as a prognostic biomarker in NSCLC immunotherapy. This study aimed to investigate the predictive role of IRF4 expression in patients with NSCLC receiving immunotherapy.

METHODS

Data from three NSCLC cohorts treated with immune checkpoint inhibitors were collected from the Gene Expression Omnibus (GEO) database. The prognostic significance of IRF4 was assessed across these cohorts, and gene set enrichment analysis (GSEA) was performed. IRF4-based nomograms were developed to predict the outcomes of immunotherapy. Correlations among IRF4 expression, immune cell infiltration, and immunotherapy prognosis were evaluated in our cohort.

RESULTS

Elevated IRF4 expression was associated with improved prognosis in patients with NSCLC undergoing immunotherapy, consistent with both GEO dataset and our cohort. IRF4 emerged as an independent predictor for progression-free survival (PFS) and overall survival (OS) in multivariable Cox regression analysis. GSEA analysis highlighted links between IRF4 expression and immune activation pathways such as Chemokine_Signaling_Pathway, Natural_Killer_Cell_Mediated_Cytotoxicity, B_Cell_Receptor_Signaling_Pathway, and T_Cell_Receptor_Signaling_Pathway. In our cohort, immunohistochemistry demonstrated correlations between IRF4 expression and the infiltration of CD8+ T cells, CD20+ B cells, and PD-L1 expression in the tumor microenvironment.

CONCLUSION

High IRF4 expression in baseline tumor tissue could serve as a favorable predictor of NSCLC immunotherapy outcomes, aiding in personalized treatment strategies.

Immune Checkpoints in B Cells: Unlocking New Potentials in Cancer Treatment

B cells are crucial component of humoral immunity, and their role in the tumor immune microenvironment (TME) has garnered significant attention in recent years. These cells hold great potential and application prospects in the field of tumor immunotherapy. Research has demonstrated that the TME can remodel various B cell functions, including proliferation, differentiation, antigen presentation, and antibody production, thereby invalidating the anti-tumor effects of B cells. Concurrently, numerous immune checkpoints (ICs) on the surface of B cells are upregulated. Aberrant B-cell IC signals not only impair the function of B cells themselves, but also modulate the tumor-killing effects of other immune cells, ultimately fostering an immunosuppressive TME and facilitating tumor immune escape. Blocking ICs on B cells is beneficial for reversing the immunosuppressive TME and restoring anti-tumor immune responses. In this paper, the intricate connection between B-cell ICs and the TME is delved into, emphasizing the critical role of targeting B-cell ICs in anti-tumor immunity, which may provide valuable insights for the future development of tumor immunotherapy based on B cells.

Cell Identity and Spatial Distribution of PD-1/PD-L1 Blockade Responders

The programmed death 1 (PD-1)/programmed death ligand 1 (PD-L1) axis inhibits T cell activity, impairing anti-tumor immunity. Blocking this axis with therapeutic antibodies is one of the most promising anti-tumor immunotherapies. It has long been recognized that PD-1/PD-L1 blockade reinvigorates exhausted T (TEX) cells already present in the tumor microenvironment (TME). However, recent advancements in high-throughput gene sequencing and bioinformatic tools have provided researchers with a more granular and dynamic insight into PD-1/PD-L1 blockade-responding cells, extending beyond the TME and TEX populations. This review provides an update on the cell identity, spatial distribution, and treatment-induced spatiotemporal dynamics of PD-1/PD-L1 blockade responders. It also provides a synopsis of preliminary reports of potential PD-1/PD-L1 blockade responders other than T cells to depict a panoramic picture. Important questions to answer in further studies and the translational and clinical potential of the evolving understandings are also discussed.

Tertiary lymphoid structures as potential biomarkers for cancer prediction and prognosis

Tertiary lymphoid structures (TLSs) are ectopic lymphocyte aggregates formed in non-lymphoid tissues, including cancers, and are loci for the generation of in situ anti-tumor immune responses, which play a crucial role in cancer control. The state of TLS presence in cancer and its composition can significantly impact the treatment response and prognosis of patients. TLSs have the potential to serve as predictive and prognostic biomarkers for cancer. However, the mechanisms underlying TLS formation in cancer and how the essential components of TLSs affect cancer are not fully understood. In this review, we summarized TLS formation in cancer, the value of the TLS in different states of existence, and its key constituents for cancer prediction and prognosis. Finally, we discussed the impact of cancer treatment on TLSs.

Tertiary Lymphoid Structures in Microorganism-Related Cancer

Tertiary lymphoid structures (TLSs) are ectopic lymphoid tissues formed by the accumulation of lymphocytes and other components outside lymphoid organs. They have been shown to be widespread in cancers and have predictive effects on prognosis and immunotherapy efficacy; however, there is no standardized measurement guide. This paper provides a reference for future research. Moreover, the induction strategy for the formation mechanism of TLSs is a new direction for future cancer treatment, such as cancer vaccines for microorganisms. The effects of microorganisms on cancer are dual. The role of microorganisms, including bacteria, parasites, viruses, and fungi, in promoting cancer has been widely confirmed. However, the specific mechanism of their tumor suppressor effect, particularly the promotion of TLS formation, is currently unknown. In this review, we summarize the role of TLSs in cancer related to microbial infection and provide new ideas for further understanding their mechanisms of action in cancer.

Macrophages and tertiary lymphoid structures as indicators of prognosis and therapeutic response in cancer patients

Tertiary lymphoid structures (TLS) can reflect cancer prognosis and clinical outcomes in various tumour tissues. Tumour-associated macrophages (TAMs) are indispensable components of the tumour microenvironment and play crucial roles in tumour development and immunotherapy. TAMs are associated with TLS induction via the modulation of the T cell response, which is a major component of the TLS. Despite their important roles in cancer immunology, the subtypes of TAMs that influence TLS and their correlation with prognosis are not completely understood. Here, we provide novel insights into the role of TAMs in regulating TLS formation. Furthermore, we discuss the prognostic value of these TAM subtypes and TLS, as well as the current antitumour therapies for inducing TLS. This study highlights an entirely new field of TLS regulation that may lead to the development of an innovative perspective on immunotherapy for cancer treatment.

Tertiary lymphoid structures in diseases: immune mechanisms and therapeutic advances

Tertiary lymphoid structures (TLSs) are defined as lymphoid aggregates formed in non-hematopoietic organs under pathological conditions. Similar to secondary lymphoid organs (SLOs), the formation of TLSs relies on the interaction between lymphoid tissue inducer (LTi) cells and lymphoid tissue organizer (LTo) cells, involving multiple cytokines. Heterogeneity is a distinguishing feature of TLSs, which may lead to differences in their functions. Growing evidence suggests that TLSs are associated with various diseases, such as cancers, autoimmune diseases, transplant rejection, chronic inflammation, infection, and even ageing. However, the detailed mechanisms behind these clinical associations are not yet fully understood. The mechanisms by which TLS maturation and localization affect immune function are also unclear. Therefore, it is necessary to enhance the understanding of TLS development and function at the cellular and molecular level, which may allow us to utilize them to improve the immune microenvironment. In this review, we delve into the composition, formation mechanism, associations with diseases, and potential therapeutic applications of TLSs. Furthermore, we discuss the therapeutic implications of TLSs, such as their role as markers of therapeutic response and prognosis. Finally, we summarize various methods for detecting and targeting TLSs. Overall, we provide a comprehensive understanding of TLSs and aim to develop more effective therapeutic strategies.

The roles of tertiary lymphoid structures in genitourinary cancers: molecular mechanisms, therapeutic strategies, and clinical applications

The presence of tertiary lymphoid structures (TLSs) associated with distinct treatment efficacy and clinical prognosis has been identified in various cancer types. However, the mechanistic roles and clinical implications of TLSs in genitourinary (GU) cancers remain incompletely explored. Despite their potential role as predictive markers described in numerous studies, it is essential to comprehensively evaluate the characteristics of TLSs, including drivers of formation, structural foundation, cellular compositions, maturation stages, molecular features, and specific functionality to maximize their positive impacts on tumor-specific immunity. The unique contributions of these structures to cancer progression and biology have fueled interest in these structures as mediators of antitumor immunity. Emerging data are trying to explore the effects of therapeutic interventions targeting TLSs. Therefore, a better understanding of the molecular and phenotypic heterogeneity of TLSs may facilitate the development of TLSs-targeting therapeutic strategies to obtain optimal clinical benefits for GU cancers in the setting of immunotherapy. In this review, the authors focus on the phenotypic and functional heterogeneity of TLSs in cancer progression, current therapeutic interventions targeting TLSs and the clinical implications and therapeutic potential of TLSs in GU cancers.

Mature tertiary lymphoid structures: important contributors to anti-tumor immune efficacy

Tertiary lymphoid structures (TLS) represent the ectopic aggregations of immune cells arising during chronic inflammation or tumor progression. In cancer, TLS are often associated with beneficial clinical outcomes in patients undergoing immunotherapy, underscoring their prognostic and predictive significance. Mature TLS, characterized by germinal centers and areas of T-cell and B-cell aggregation, are considered primary locations for activating and maintaining both humoral and cellular anti-tumor immune effects. Despite their recognized importance, the mechanisms driving the formation of mature TLS in cancer and their influence on the immune response within tumors remain insufficiently understood. Therefore, this review aims to comprehensively explore the structural composition, development mechanisms, maturity impact factors, immunological function, and innovative therapeutic strategies of mature TLS within the tumor microenvironment. The research summarized herein offers novel insights and considerations for therapeutic approaches to promote TLS generation and maturation in patients with cancer, representing a promising avenue for future cancer therapies.

Exploiting Tertiary Lymphoid Structures to Stimulate Antitumor Immunity and Improve Immunotherapy Efficacy

Tumor-associated tertiary lymphoid structures (TLS) have been associated with favorable clinical outcomes and response to immune checkpoint inhibitors in many cancer types, including non-small cell lung cancer. Although the detailed cellular and molecular mechanisms underlying these clinical associations have not been fully elucidated, growing preclinical and clinical studies are helping to elucidate the mechanisms at the basis of TLS formation, composition, and regulation of immune responses. However, a major challenge remains how to exploit TLS to enhance naïve and treatment-mediated antitumor immune responses. Here, we discuss the current understanding of tumor-associated TLS, preclinical models that can be used to study them, and potential therapeutic interventions to boost TLS formation, with a particular focus on lung cancer research.

Anti-PD-1 therapy triggers Tfh cell-dependent IL-4 release to boost CD8 T cell responses in tumor-draining lymph nodes

Anti-PD-1 therapy targets intratumoral CD8+ T cells to promote clinical responses in cancer patients. Recent evidence suggests an additional activity in the periphery, but the underlying mechanism is unclear. Here, we show that anti-PD-1 mAb enhances CD8+ T cell responses in tumor-draining lymph nodes by stimulating cytokine production in follicular helper T cells (Tfh). In two different models, anti-PD-1 mAb increased the activation and proliferation of tumor-specific T cells in lymph nodes. Surprisingly, anti-PD-1 mAb did not primarily target CD8+ T cells but instead stimulated IL-4 production by Tfh cells, the major population bound by anti-PD-1 mAb. Blocking IL-4 or inhibiting the Tfh master transcription factor BCL6 abrogated anti-PD-1 mAb activity in lymph nodes while injection of IL-4 complexes was sufficient to recapitulate anti-PD-1 mAb activity. A similar mechanism was observed in a vaccine model. Finally, nivolumab also boosted human Tfh cells in humanized mice. We propose that Tfh cells and IL-4 play a key role in the peripheral activity of anti-PD-1 mAb.

Tertiary lymphoid structures predict survival and response to neoadjuvant therapy in locally advanced rectal cancer

Tertiary lymphoid structure (TLS) contributes to the anti-tumor immune response, and predicts the prognosis of colorectal cancer patients. However, the potential impact of TLS in shaping the immune status of rectal adenocarcinoma, and the intrinsic relationship between TLS and neoadjuvant therapies (neoTx) remain unclear. We performed hematoxylin-eosin staining, immunohistochemical and biomolecular analyses to investigate TLS and tumor-infiltrating lymphocytes (TILs) in 221 neoTx-treated and 242 treatment-naïve locally advanced rectal cancer (LARC) patients. High TLS density was significantly associated with the absence of vascular invasion, a lower neutrophil-to-lymphocyte ratio, increased TLS maturity, a longer recurrence-free survival (RFS) (hazard ratio [HR] 0.2985 95% confidence interval [CI] 0.1894-0.4706, p < 0.0001) and enhanced infiltration of adaptive immune cells. Biomolecular analysis showed that high TLS-score was strongly associated with more infiltration of immune cells and increased activation of immune-related pathways. TLS+ tumors in pre-treatment specimens were associated with a higher proportion of good respond (62.5% vs. 29.8%, p < 0.0002) and pathological complete remission (pCR) (40.0% vs. 11.1%, p < 0.0001), and significantly increased RFS (HR 0.3574 95%CI 0.1489-0.8578 p = 0.0213) compared with TLS- tumors in the neoTx cohort, which was confirmed in GSE119409 and GSE150082. Further studies showed that neoTx significantly reduced TLS density and maturity, and abolished the prognostic value of TLS. Our study illustrates that TLS may have a key role in mediating the T-cell-inflamed tumor microenvironment, which also provides a new direction for neoTx, especially neoadjuvant immunotherapy, in LRAC patients.

[Recent Progress of Tertiary Lymphoid Structure in Prognosis and Immunotherapy of Non-small Cell Lung Cancer]

Lung cancer is the leading cause of cancer death, and non-small cell lung cancer (NSCLC) accounts for 85%. Immunotherapy has significantly improved the clinical prognosis of patients with NSCLC. However, because of the complexity and heterogeneousness of the tumor microenvironment, only a subset of individuals can benefit from immunotherapy. Therefore, it is necessary to explore effective predictive biomarkers for immunotherapy of NSCLC. Tertiary lymphoid structure (TLS) is an ectopic lymphoid organ that is highly similar to secondary lymphoid organs (SLO), and the presence of TLS has been found to be closely associated with a good prognosis in immunotherapy for a variety of solid tumors, including NSCLC. This article provides a review of the prognostic role of tertiary lymphoid structures in immunotherapy of NSCLC, in order to offer references for screening suitable candidates for immunotherapy of NSCLC and develop personalized and precise treatment plans.
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Tertiary lymphoid structures and B lymphocytes: a promising therapeutic strategy to fight cancer

Tertiary lymphoid structures (TLSs) are clusters of lymphoid cells with an organization that resembles that of secondary lymphoid organs. Both structures share common developmental characteristics, although TLSs usually appear in chronically inflamed non-lymphoid tissues, such as tumors. TLSs contain diverse types of immune cells, with varying degrees of spatial organization that represent different stages of maturation. These structures support both humoral and cellular immune responses, thus the correlation between the existence of TLS and clinical outcomes in cancer patients has been extensively studied. The finding that TLSs are associated with better prognosis in some types of cancer has led to the design of therapeutic strategies based on promoting the formation of these structures. Agents such as chemokines, cytokines, antibodies and cancer vaccines have been used in combination with traditional antitumor treatments to enhance TLS generation, with good results. The induction of TLS formation therefore represents a novel and promising avenue for the treatment of a number of tumor types.

B cells in tumor metastasis: friend or foe?

Metastasis is an important cause of cancer-related death. Immunotherapy may be an effective way to prevent and treat tumor metastasis in the future. Currently, many studies have focused on T cells, whereas fewer have focused on B cells and their subsets. B cells play an important role in tumor metastasis. They not only secrete antibodies and various cytokines but also function in antigen presentation to directly or indirectly participate in tumor immunity. Furthermore, B cells are involved in both inhibiting and promoting tumor metastasis, which demonstrates the complexity of B cells in tumor immunity. Moreover, different subgroups of B cells have distinct functions. The functions of B cells are also affected by the tumor microenvironment, and the metabolic homeostasis of B cells is also closely related to their function. In this review, we summarize the role of B cells in tumor metastasis, analyze the mechanisms of B cells, and discuss the current status and prospects of B cells in immunotherapy.

T follicular helper cells in cancer

T follicular helper (Tfh) cells provide essential help to B cells for effective antibody-mediated immune responses. Although the crucial function of these CD4⁺ T cells in infection and vaccination is well established, their involvement in cancer is only beginning to emerge. Increased numbers of Tfh cells in Tfh cell-derived or B cell-associated malignancies are often associated with an unfavorable outcome, whereas in various solid organ tumor types of non-lymphocytic origin, their presence frequently coincides with a better prognosis. We discuss recent advances in understanding how Tfh cell crosstalk with B cells and CD8⁺ T cells in secondary and tertiary lymphoid structures (TLS) enhances antitumor immunity, but may also exacerbate immune-related adverse events (irAEs) such as autoimmunity during immune checkpoint blockade (ICB) and cancer immunotherapy.

Tertiary lymphoid structures are critical for cancer prognosis and therapeutic response

Tertiary lymphoid structures (TLSs) are ectopic lymphocyte aggregates that form at sites of chronic inflammation, including cancers, in non-lymphoid tissues. Although the formation of TLSs is similar to that of secondary lymphoid organs, the pathogenic factors leading to TLS formation in cancerous tissues and the mechanisms underlying the role of these structures in the intra-tumoral adaptive antitumor immune response are not fully understood. The presence of TLSs may impact patient prognosis and treatment outcomes. This review examines the current understanding of TLSs in cancers, including their composition and formation as well as their potential to predict prognosis and therapeutic efficacy. We also summarize strategies to induce TLS formation for cancer treatment.

Development and validation of a mutation-based model to predict immunotherapeutic efficacy in NSCLC

Background

Immunotherapy has become increasingly important in the perioperative period of non-small-cell lung cancer (NSCLC). In this study, we intended to develop a mutation-based model to predict the therapeutic effificacy of immune checkpoint inhibitors (ICIs) in patients with NSCLC.

Methods

Random Forest (RF) classifiers were generated to identify tumor gene mutated features associated with immunotherapy outcomes. Then the best classifier with the highest accuracy served for the development of the predictive model. The correlations of some reported biomarkers with the model were analyzed, such as TMB, PD-(L)1, KEAP1-driven co-mutations, and immune subtypes. The training cohort and validation cohorts performed survival analyses to estimate the predictive efficiency independently.

Results

An 18-gene set was selected using random forest (RF) classififiers. A predictive model was developed based on the number of mutant genes among the candidate genes, and patients were divided into the MT group (mutant gene ≥ 2) and WT group (mutant gene < 2). The MT group (N = 54) had better overall survival (OS) compared to the WT group (N = 290); the median OS was not reached vs. nine months (P < 0.0001, AUC = 0.73). The robust predictive performance was confifirmed in three validation cohorts, with an AUC of 0.70, 0.57, and 0.64 (P < 0.05). The MT group was characterized by high tumor neoantigen burden (TNB), increased immune infifiltration cells such as CD8 T and macrophage cells, and upregulated immune checkpoint molecules, suggesting potential biological advantages in ICIs therapy.

Conclusions

The predictive model could precisely predict the immunotherapeutic efficacy in NSCLC based on the mutant genes within the model. Furthermore, some immune-related features and cell expression could support robust efficiency.

Impact of interaction networks of B cells with other cells on tumorigenesis, progression and response to immunotherapy of renal cell carcinoma: A review

Ample evidence indicates that the development and progression of renal cell carcinoma (RCC) are complex pathological processes involving interactions between tumor cells, immune cells and stromal components. Tumor infiltrated immune cells determine whether tumor advancement is promoted or inhibited. Among them, infiltrated B lymphocytes are present in all stages of RCC, playing a major role in determining tumor formation and advancement, as an essential part in the tumor microenvironment (TME). Although the advent of targeted and immune therapies has remarkably improved the survival of patients with advanced RCC, few cases can achieve complete response due to drug resistance. In this review article, we intend to summary the recent studies that outline the interaction networks of B cells with other cells, discuss the role of B cells in RCC development and progression, and assess their impact on RCC immunotherapy.

Maturation and abundance of tertiary lymphoid structures are associated with the efficacy of neoadjuvant chemoimmunotherapy in resectable non-small cell lung cancer

Tertiary lymphoid structures (TLS) existence is correlated with favorable prognosis in many types of cancer including non-small cell lung cancer (NSCLC). However, TLS formation and its relationship with treatment response remains unknown in NSCLC who received anti-PD-1 antibody plus chemotherapy as the neoadjuvant treatment (neoadjuvant chemoimmunotherapy). Here, we investigate TLS maturation and abundance in resectable NSCLC receiving neoadjuvant treatments. We retrospectively collected formalin-fixed paraffin embedded (FFPE) tissues from patients with resectable NSCLC (stage II–IIIA) from three cohorts based on treatment: naïve (N=40), neoadjuvant chemoimmunotherapy (N=40), and neoadjuvant chemotherapy (N=41). The TLS in tumor tissues was detected by immunohistochemical staining, and the differences in TLS maturation and abundance among different treatment groups were analyzed, as well as the relationship with pathological response and prognosis of patients. Multiplex immunofluorescence staining was used to explore the features of immune microenvironment. Higher major pathological response (MPR) rate and pathological complete response (pCR) rate were in the neoadjuvant chemoimmunotherapy group than in the neoadjuvant chemotherapy group (MPR: 45.0% vs 17.1%; pCR: 35.0% vs 4.9%). Among the three cohorts, neoadjuvant chemoimmunotherapy-treated NSCLCs displayed highest TLS maturation and abundance. Both the maturation and abundance of TLS were significantly correlated with MPR in both the neoadjuvant chemoimmunotherapy and the chemotherapy group. Patients with high maturation and abundance of TLS exhibited better disease-free survival (DFS) in all the three cohorts. TLS maturation was also an independent predictor for DFS in the neoadjuvant chemoimmunotherapy and treatment naïve group. Multiplex immunohistochemistry analysis using paired biopsy-surgery samples showed increased infiltration of CD8+T cell and decreased infiltration of M1 and M2 macrophages after neoadjuvant chemoimmunotherapy treatment in patients achieving MPR. There were no significant differences in features of immune cell infiltration for those with mature TLS achieving MPR when cross-compared across the three cohorts. These results demonstrate that TLS maturation is associated with MPR and an independent predictor for DFS in resectable neoadjuvant chemoimmunotherapy-treated NSCLC. The induction of TLS maturation may be a potential mechanism of action of neoadjuvant chemoimmunotherapy in resectable NSCLC.

The depths of PD-1 function within the tumor microenvironment beyond CD8+ T cells

Programmed cell death-1 (PD-1; CD279) is a cell surface receptor that is expressed in both innate and adaptive immune cells. The role of PD-1 in adaptive immune cells, specifically in CD8+ T cells, has been thoroughly investigated but its significance in other immune cells is yet to be well established. This review will address the role of PD-1 based therapies in enhancing non-CD8+ T cell immune responses within cancer. Specifically, the expression and function of PD-1 in non-CD8+ immune cell compartments such as CD4+ T helper cell subsets, myeloid cells and innate lymphoid cells (ILCs) will be discussed. By understanding the immune cell specific function of PD-1 within tissue resident innate and adaptive immune cells, it will be possible to stratify patients for PD-1 based therapies for both immunogeneic and non-immunogeneic neoplastic disorders. With this knowledge from fundamental and translational studies, PD-1 based therapies can be utilized to enhance T cell independent immune responses in cancers.

RNA modification writer expression profiles predict clinical outcomes and guide neoadjuvant immunotherapy in non-small cell lung cancer

Background

RNA modifications, including adenosine-to-inosine RNA editing, alternative polyadenylation, m¹A and m⁶A, play a significant role in tumorigenesis and tumor immunity. However, the functions of RNA modification enzymes (writers) in immunotherapy and tumor microenvironment (TME) remain unknown.

Methods

Nonnegative matrix factorization clustering was applied to identify RNA modification clusters in lung adenocarcinoma, one of the most prevalent subtypes of non-small cell lung cancer (NSCLC). CIBERSORT and ESTIMATE algorithms were performed to depict TME characteristics. Additionally, a scoring system called Writer-Score was established to quantify RNA modification patterns and subsequently predict clinical outcomes. We subsequently used RNA sequencing, targeted DNA sequencing and multiplex immunofluorescence to further evaluate the efficacy of Writer-Score in NSCLC patients receiving neoadjuvant immunotherapy.

Findings

We identified three distinct RNA modification clusters and two DEGclusters, which were shown to be strongly associated with a variety of TME features and biological processes. Additionally, the Writer-Score served as an important factor in post-transcriptional events and immunotherapy. The Writer-Score was capable of properly predicting the prognosis of NSCLC patients receiving neoadjuvant PD-1 inhibitor therapy.

Interpretation

Our work systematically analyzed four types of RNA modifications and constructed a scoring system to guide neoadjuvant immunotherapy in NSCLC, which highlighted the writers’ roles in post-transcriptional events, TME and neoadjuvant immunotherapy.

Funding

A full list of funding bodies that supported this study can be found in the Acknowledgements section.

Heterogeneity and Functions of Tumor-Infiltrating Antibody Secreting Cells: Lessons from Breast, Ovarian, and Other Solid Cancers

Simple Summary

B cells are gaining increasing recognition as important contributors to the tumor microenvironment, influencing, positively or negatively, tumor growth, patient survival, and response to therapies. Antibody secreting cells (ASCs) constitute a variable fraction of tumor-infiltrating B cells in most solid tumors, and they produce tumor-specific antibodies that can drive distinct immune responses depending on their isotypes and specificities. In this review, we discuss the current knowledge of the heterogeneity of ASCs infiltrating solid tumors and how both their canonical and noncanonical functions shape antitumor immunity, with a special emphasis on breast and ovarian cancers.

Abstract

Neglected for a long time in cancer, B cells and ASCs have recently emerged as critical actors in the tumor microenvironment, with important roles in shaping the antitumor immune response. ASCs indeed exert a major influence on tumor growth, patient survival, and response to therapies. The mechanisms underlying their pro- vs. anti-tumor roles are beginning to be elucidated, revealing the contributions of their secreted antibodies as well as of their emerging noncanonical functions. Here, concentrating mostly on ovarian and breast cancers, we summarize the current knowledge on the heterogeneity of tumor-infiltrating ASCs, we discuss their possible local or systemic origin in relation to their immunoglobulin repertoire, and we review the different mechanisms by which antibody (Ab) subclasses and isoforms differentially impact tumor cells and anti-tumor immunity. We also discuss the emerging roles of cytokines and other immune modulators produced by ASCs in cancer. Finally, we propose strategies to manipulate the tumor ASC compartment to improve cancer therapies.

Tumour-infiltrating B cells: immunological mechanisms, clinical impact and therapeutic opportunities

Although immunotherapy research to date has focused largely on T cells, there is mounting evidence that tumour-infiltrating B cells and plasma cells (collectively referred to as tumour-infiltrating B lymphocytes (TIL-Bs)) have a crucial, synergistic role in tumour control. In many cancers, TIL-Bs have demonstrated strong predictive and prognostic significance in the context of both standard treatments and immune checkpoint blockade, offering the prospect of new therapeutic opportunities that leverage their unique immunological properties. Drawing insights from autoimmunity, we review the molecular phenotypes, architectural contexts, antigen specificities, effector mechanisms and regulatory pathways relevant to TIL-Bs in human cancer. Although the field is young, the emerging picture is that TIL-Bs promote antitumour immunity through their unique mode of antigen presentation to T cells; their role in assembling and perpetuating immunologically 'hot' tumour microenvironments involving T cells, myeloid cells and natural killer cells; and their potential to combat immune editing and tumour heterogeneity through the easing of self-tolerance mechanisms. We end by discussing the most promising approaches to enhance TIL-B responses in concert with other immune cell subsets to extend the reach, potency and durability of cancer immunotherapy.

Baseline circulating unswitched memory B cells and B-cell related soluble factors are associated with overall survival in patients with clear cell renal cell carcinoma treated with nivolumab within the NIVOREN GETUG-AFU 26 study

BACKGROUND

The phase II NIVOREN GETUG-AFU 26 study reported safety and efficacy of nivolumab in patients with metastatic clear cell renal cell carcinoma (m-ccRCC) in a 'real-world setting'. We conducted a translational-research program to determine whether specific circulating immune-cell populations and/or soluble factors at baseline were predictive of clinical outcomes in patients with m-ccRCC treated with nivolumab within the NIVOREN study.

METHODS

Absolute numbers of 106 circulating immune-cell populations were prospectively analyzed in patients treated at a single institution within the NIVOREN trial with available fresh-whole-blood, using dry formulation panels for multicolor flow cytometry. In addition, a panel of 14 predefined soluble factors was quantified for each baseline plasma sample using the Meso-Scale-Discovery immunoassay. The remaining patients with available plasma sample were used as a validation cohort for the soluble factor quantification analysis. Tumor immune microenvironment characterization of all patients included in the translational program of the study was available. The association of blood and tissue-based biomarkers, with overall survival (OS), progression-free survival (PFS) and response was analyzed.

RESULTS

Among the 44 patients, baseline unswitched memory B cells (NSwM B cells) were enriched in responders (p=0.006) and associated with improved OS (HR=0.08, p=0.002) and PFS (HR=0.54, p=0.048). Responders were enriched in circulating T follicular helper (Tfh) (p=0.027) and tertiary lymphoid structures (TLS) (p=0.043). Circulating NSwM B cells positively correlated with Tfh (r=0.70, p<0.001). Circulating NSwM B cells correlated positively with TLS and CD20 +B cells at the tumor center (r=0.59, p=0.044, and r=0.52, p=0.033) and inversely correlated with BCA-1/CXCL13 and BAFF (r=-0.55 and r=-0.42, p<0.001). Tfh cells also inversely correlated with BCA-1/CXCL13 (r=-0.61, p<0.001). IL-6, BCA-1/CXCL13 and BAFF significantly associated with worse OS in the discovery (n=40) and validation cohorts (n=313).

CONCLUSION

We report the first fresh blood immune-monitoring of patients with m-ccRCC treated with nivolumab. Baseline blood concentration of NSwM B cells was associated to response, PFS and OS in patients with m-ccRCC treated with nivolumab. BCA-1/CXCL13 and BAFF, inversely correlated to NSwM B cells, were both associated with worse OS in discovery and validation cohorts. Our data confirms a role for B cell subsets in the response to immune checkpoint blockade therapy in patients with m-ccRCC. Further studies are needed to confirm these findings.

B cells and tertiary lymphoid structures as determinants of tumour immune contexture and clinical outcome

B cells are a major component of the tumour microenvironment, where they are predominantly associated with tertiary lymphoid structures (TLS). In germinal centres within mature TLS, B cell clones are selectively activated and amplified, and undergo antibody class switching and somatic hypermutation. Subsequently, these B cell clones differentiate into plasma cells that can produce IgG or IgA antibodies targeting tumour-associated antigens. In tumours without mature TLS, B cells are either scarce or differentiate into regulatory cells that produce immunosuppressive cytokines. Indeed, different tumours vary considerably in their TLS and B cell content. Notably, tumours with mature TLS, a high density of B cells and plasma cells, as well as the presence of antibodies to tumour-associated antigens are typically associated with favourable clinical outcomes and responses to immunotherapy compared with those lacking these characteristics. However, polyclonal B cell activation can also result in the formation of immune complexes that trigger the production of pro-inflammatory cytokines by macrophages and neutrophils. In complement-rich tumours, IgG antibodies can also activate the complement cascade, resulting in the production of anaphylatoxins that sustain tumour-promoting inflammation and angiogenesis. Herein, we review the phenotypic heterogeneity of intratumoural B cells and the importance of TLS in their generation as well as the potential of B cells and TLS as prognostic and predictive biomarkers. We also discuss novel therapeutic approaches that are being explored with the aim of increasing mature TLS formation, B cell differentiation and anti-tumour antibody production within tumours.

Adenovirus Encoding Tumor Necrosis Factor Alpha and Interleukin 2 Induces a Tertiary Lymphoid Structure Signature in Immune Checkpoint Inhibitor Refractory Head and Neck Cancer

Immune checkpoint inhibitors (ICI) have provided significant improvement in clinical outcomes for some patients with solid tumors. However, for patients with head and neck cancer, the response rate to ICI monotherapy remains low, leading to the exploration of combinatorial treatment strategies. In this preclinical study, we use an oncolytic adenovirus (Ad5/3) encoding hTNFα and hIL-2 and non-replicate adenoviruses (Ad5) encoding mTNFα and mIL-2 with ICI to achieve superior tumor growth control and improved survival outcomes. The in vitro effect of Ad5/3-E2F-D24-hTNFa-IRES-hIL-2 was characterized through analyses of virus replication, transgene expression and lytic activity using head and neck cancer patient derived cell lines. Mouse models of ICI naïve and refractory oral cavity squamous cell carcinoma were established to evaluate the local and systemic anti-tumor immune response upon ICI treatment with or without the non-replicative adenovirus encoding mTNFα and mIL-2. We delineated the mechanism of action by measuring the metabolic activity and effector function of CD3+ tumor infiltrating lymphocytes (TIL) and transcriptomic profile of the CD45+ tumor immune compartment. Ad5/3-E2F-D24-hTNFa-IRES-hIL-2 demonstrated robust replicative capability in vitro across all head and neck cell lines screened through potent lytic activity, E1a and transgene expression. In vivo, in both ICI naïve and refractory models, we observed improvement to tumor growth control and long-term survival when combining anti-PD-1 or anti-PD-L1 with the non-replicative adenovirus encoding mTNFα and mIL-2 compared to monotherapies. This observation was verified by striking CD3+ TIL derived mGranzyme b and interferon gamma production complemented by increased T cell bioenergetics. Notably, interrogation of the tumor immune transcriptome revealed the upregulation of a gene signature distinctive of tertiary lymphoid structure formation upon treatment of murine anti-PD-L1 refractory tumors with non-replicative adenovirus encoding mTNFα and mIL-2. In addition, we detected an increase in anti-tumor antibody production and expansion of the memory T cell compartment in the secondary lymphoid organs. In summary, a non-replicative adenovirus encoding mTNFα and mIL-2 potentiates ICI therapy, demonstrated by improved tumor growth control and survival in head and neck tumor-bearing mice. Moreover, the data reveals a potential approach for inducing tertiary lymphoid structure formation. Altogether our results support the clinical potential of combining this adenovirotherapy with anti-PD-1 or anti-PD-L1.

Tertiary lymphoid structures in cancer

Ectopic lymphoid aggregates, termed tertiary lymphoid structures (TLSs), are formed in numerous cancer types, and, with few exceptions, their presence is associated with superior prognosis and response to immunotherapy. In spite of their presumed importance, the triggers that lead to TLS formation in cancer tissue and the contribution of these structures to intratumoral immune responses remain incompletely understood. Here, we discuss the present knowledge on TLSs in cancer, focusing on (i) the drivers of TLS formation, (ii) the function and contribution of TLSs to the antitumor immune response, and (iii) the potential of TLSs as therapeutic targets in human cancers.

The role of B cells in the development, progression, and treatment of lymphomas and solid tumors

B cells are integral components of the mammalian immune response as they have the ability to generate antibodies against an almost infinite array of antigens. Over the past several decades, significant scientific progress has been made in understanding that this enormous B cell diversity contributes to pathogen clearance. However, our understanding of the humoral response to solid tumors and to tumor-specific antigens is unclear. In this review, we first discuss how B cells interact with other cells in the tumor microenvironment and influence the development and progression of various solid tumors. The ability of B lymphocytes to generate antibodies against a diverse repertoire of antigens and subsequently tailor the humoral immune response to specific pathogens relies on their ability to undergo genomic alterations during their development and differentiation. We will discuss key transforming events that lead to the development of B cell lymphomas. Overall, this review provides a foundation for innovative therapeutic interventions for both lymphoma and solid tumor malignancies.

Lower baseline autoantibody levels are associated with immune-related adverse events from immune checkpoint inhibition

INTRODUCTION

Immune checkpoint inhibitors (ICI) are a novel cancer therapeutic that have been successful in treating advanced malignancies; however, they also cause immune-related adverse events (irAE). Given that some irAE are clinically similar to traditional autoimmune diseases, autoantibodies have been suggested as possible biomarkers of irAE. However, there are very little data on autoantibody investigation prior to ICI. Our aim was to determine if specific baseline autoantibodies were associated with irAE and see if changes in autoantibody concentration corresponded with irAE development.

METHODS

This study used data from an oncologic clinical trial of adaptive dosing combination ICI therapy in patients with advanced melanoma. Plasma was collected at baseline and 6 weeks after ICI initiation and tested in a microarray of 120 autoantigens commonly associated with autoimmune disease, as well as antinuclear antibody (ANA), rheumatoid factor (RF), and anti-cyclic citrullinated peptide antibody (anti-CCP). Autoantibody concentrations were compared between patients experiencing an organ-specific event versus not. Heatmaps, volcano plots and hierarchical clustering were used to determine autoantibody concentration differences among irAE patient clusters as defined by signal intensity of autoantibodies. Kaplan-Meier curves were created and a log-rank test was performed to assess differences in survival.

RESULTS

The microarray analysis demonstrated that patients who experienced specific irAE had fewer differentially expressed autoantibodies at baseline than those that did not have those specific irAE, and a greater fold change (FC) in antibody concentration from baseline to 6 weeks corresponded with specific irAE development. However, no autoantibodies were identified as being predictive of specific events. Time to first irAE was less than 6 weeks in 69% of patients, and these patients had less autoantibodies at baseline. Considering ANA, RF and CCP autoantibodies, there were no significant differences between the seropositive and seronegative patients in irAE development, severity, timing or survival.

CONCLUSION

Patients with low autoantibody concentrations at baseline as well as a greater FC in autoantibody concentration over 6 weeks developed more distinct organ-specific irAE. This may suggest differences in the balance of cellular immunity and humoral pathways that are relevant in the pathogenesis of irAE, though further investigation is needed.

Differential Role of PD-1 Expressed by Various Immune and Tumor Cells in the Tumor Immune Microenvironment: Expression, Function, Therapeutic Efficacy, and Resistance to Cancer Immunotherapy

In the tumor immune microenvironment (TIME), tumor cells interact with various cells and operate various strategies to avoid antitumor immune responses. These immune escape strategies often make the TIME resistant to cancer immunotherapy. Neutralizing immune escape strategies is necessary to overcome resistance to cancer immunotherapy. Immune checkpoint receptors (ICRs) expressed in effector immune cells inhibit their effector function via direct interaction with immune checkpoint ligands (ICLs) expressed in tumor cells. Therefore, blocking ICRs or ICLs has been developed as a promising cancer immunotherapy by reinvigorating the function of effector immune cells. Among the ICRs, programmed cell death 1 (PD-1) has mainly been antagonized to enhance the survival of human patients with cancer by restoring the function of tumor-infiltrating (TI) CD8⁺ T cells. It has been demonstrated that PD-1 is expressed not only in TI CD8⁺ T cells, but also in other TI immune cells and even tumor cells. While PD-1 suppresses the function of TI CD8⁺ T cells, it is controversial whether PD-1 suppresses or amplifies the suppressive function of TI-suppressive immune cells (e.g., regulatory T cells, tumor-associated macrophages, and myeloid cells). There is also controversy regarding the role of tumor-expressing PD-1. Therefore, a precise understanding of the expression pattern and function of PD-1 in each cell subset is important for improving the efficacy of cancer immunotherapy. Here, we review the differential role of PD-1 expressed by various TI immune cells and tumor cells. We focused on how cell-type-specific ablation or blockade of PD-1 affects tumor growth in a murine tumor model. Furthermore, we will also describe how the blockade of PD-1 acts on TI immune cells in human patients with cancer.

Identification of Three Core Secretome Genes Associated with Immune Infiltration in High Tumor Mutation Burden Across 14 Major Solid Tumors

Background

Secretome genes, encoding proteins secreted from the cell, are involved in the tumor immune response and correlated with levels of tumor mutation burden (TMB) in multiple tumors. This study aimed to identify core secretome genes and their potential association with immunomodulators and immune infiltration in high TMB groups across 14 major solid tumors through bioinformatics analysis.

Methods

Multi-omics data for 14 major solid tumors were downloaded from The Cancer Genome Atlas (TCGA) database. Patients were divided into high TMB (TMB-high) and low TMB (TMB-low) groups using the median TMB values for each of the solid tumors. The CIBERSORT algorithm was conducted to estimate the proportion of 22 tumor-infiltrating immune cells (TIICs). Kaplan-Meier analysis and the log-rank test were utilized to screened prognosis-related genes. The correlations between core secretome genes and TIICs were analyzed using Spearman correlation coefficients.

Results

In TMB-high groups, multi-omics data analysis revealed that secretome genes were strongly associated with clinical characteristics, and 65 prognosis-related secretome genes were screened. Among the prognosis-related genes, 21 core secretome genes were identified, and strongly associated with five types of TIICs, namely activated NK cells, follicular helper T cells, CD8 T cells, and macrophages M0 and M2. Notably, three secretome genes (ADAMTS12, COL12A1, and COL5A2) were significantly related to immunomodulators and TIICs in multiple solid tumors. In addition, 12 core secretome genes were significantly differentially expressed between responding and non-responding patients receiving immunotherapy. Furthermore, core secretome genes may be involved in the PI3K/AKT signaling pathway.

Conclusion

We examined the prognostic significance of secretome genes and their potential association with immunomodulators and immune infiltration across 14 major solid tumors. In summary, three secretome genes (ADAMTS12, COL12A1, and COL5A2) may be pivotal mediators of immune infiltration in TMB-high patients, which may help to identify patients who could benefit from immunotherapy.

T-Cell Responses in Merkel Cell Carcinoma: Implications for Improved Immune Checkpoint Blockade and Other Therapeutic Options

Merkel cell carcinoma (MCC) is a rare and aggressive skin cancer with rising incidence and high mortality. Approximately 80% of the cases are caused by the human Merkel cell polyomavirus, while the remaining 20% are induced by UV light leading to mutations. The standard treatment of metastatic MCC is the use of anti-PD-1/-PD-L1-immune checkpoint inhibitors (ICI) such as Pembrolizumab or Avelumab, which in comparison with conventional chemotherapy show better overall response rates and longer duration of responses in patients. Nevertheless, 50% of the patients do not respond or develop ICI-induced, immune-related adverse events (irAEs), due to diverse mechanisms, such as down-regulation of MHC complexes or the induction of anti-inflammatory cytokines. Other immunotherapeutic options such as cytokines and pro-inflammatory agents or the use of therapeutic vaccination offer great ameliorations to ICI. Cytotoxic T-cells play a major role in the effectiveness of ICI, and tumour-infiltrating CD8⁺ T-cells and their phenotype contribute to the clinical outcome. This literature review presents a summary of current and future checkpoint inhibitor therapies in MCC and demonstrates alternative therapeutic options. Moreover, the importance of T-cell responses and their beneficial role in MCC treatment is discussed.

Tumor-Associated Tertiary Lymphoid Structures: From Basic and Clinical Knowledge to Therapeutic Manipulation

The tumor microenvironment is a complex ecosystem almost unique to each patient. Most of available therapies target tumor cells according to their molecular characteristics, angiogenesis or immune cells involved in tumor immune-surveillance. Unfortunately, only a limited number of patients benefit in the long-term of these treatments that are often associated with relapses, in spite of the remarkable progress obtained with the advent of immune checkpoint inhibitors (ICP). The presence of “hot” tumors is a determining parameter for selecting therapies targeting the patient immunity, even though some of them still do not respond to treatment. In human studies, an in-depth analysis of the organization and interactions of tumor-infiltrating immune cells has revealed the presence of an ectopic lymphoid organization termed tertiary lymphoid structures (TLS) in a large number of tumors. Their marked similarity to secondary lymphoid organs has suggested that TLS are an “anti-tumor school” and an “antibody factory” to fight malignant cells. They are effectively associated with long-term survival in most solid tumors, and their presence has been recently shown to predict response to ICP inhibitors. This review discusses the relationship between TLS and the molecular characteristics of tumors and the presence of oncogenic viruses, as well as their role when targeted therapies are used. Also, we present some aspects of TLS biology in non-tumor inflammatory diseases and discuss the putative common characteristics that they share with tumor-associated TLS. A detailed overview of the different pre-clinical models available to investigate TLS function and neogenesis is also presented. Finally, new approaches aimed at a better understanding of the role and function of TLS such as the use of spheroids and organoids and of artificial intelligence algorithms, are also discussed. In conclusion, increasing our knowledge on TLS will undoubtedly improve prognostic prediction and treatment selection in cancer patients with key consequences for the next generation immunotherapy.

T follicular helper cells: linking cancer immunotherapy and immune-related adverse events

Cancer immunotherapy utilizing immune checkpoint inhibitors (ICIs) has revolutionized the treatment of numerous cancer types. As the underlying mechanism of these treatments lies in the interference with inhibitory signals that usually impair potent antitumor immunity, for example, cytotoxic T-lymphocyte-associated protein 4 (CTLA-4) and the programmed cell death protein 1 (PD-1):programmed death-ligand 1/2 (PD-L1/2) pathway, it is not surprising that this could also promote exaggerated adaptive immune responses to unrelated antigen specificities. One of the side effects of ICI-based cancer immunotherapy that is increasingly observed in the clinic is immune-related adverse events (irAEs), including various types of autoimmunity. However, the precise etiology is incompletely understood. T follicular helper (Tfh) cells provide essential help to B cells for potent antibody responses and their tumor tissue presence is often correlated with a better outcome in several solid tumor entities. Importantly, these CD4⁺ T cells express very high amounts of PD-1 and other co-stimulatory and inhibitory receptors. Here, we address the hypothesis that targeting CTLA-4 or PD-1 and its ligand PD-L1 critically impacts the function of Tfh cells in patients that receive these ICIs, thereby providing a link between ICI treatment and the development of secondary autoimmunity.