Heterogeneity in tertiary lymphoid structure B-cells correlates with patient survival in metastatic melanoma

Spatial tertiary lymphoid structures imply response to anti-PD-1 plus anlotinib in advanced non-small cell lung cancer

Despite breakthroughs of immunotherapy synergistically combined with blockade of vascular endothelial growth factor receptor, several patients with advanced non-small cell lung cancer (NSCLC) experience non-response or followed relapse. Organized lymphoid aggregates, termed tertiary lymphoid structures (TLSs), are found to be associated with improved response to immunotherapy. Here, we explore the landscapes of TLSs in tumour tissues from a real-world retrospective study. Our investigation showed that with a median follow-up of 11.2 months, the ORR was 28.6% (18/63, 95% CI 17.9-41.3) and the median PFS was 6.1 (95% CI 5.5-6.6) months in NSCLC patients treated with PD-1 blockade combined with anlotinib. By multiplex immunofluorescence (mIF) analysis, spatially, more TLSs and high CD20+ B-cell ratio in TLSs were associated with higher ORR. High density of intratumoral CD8+ T cells showed better ORR and PFS. The numbers of CD8+ T cells with a distance within 20 μm and 20-50 μm between tumour cells were higher in responders than non-responders. But responders had significantly higher TLSs within 20 μm rather than within 20-50 μm of tumour cells than non-responders. The inflamed immunophenotyping occupied higher proportions in responders and was associated with better PFS. Besides, tumour cells in non-responders were found more temporal cell-in-cell structures than responders, which could protect inner cells from T-cell attacks. Taken together, landscape of TLSs and proximity architecture may imply superior responses to PD-1 blockade combined with anlotinib for patients with advanced non-small cell lung cancer.

Lymphocyte Function in Tertiary Lymphoid Structures Predicts Hepatocellular Carcinoma Outcome

An increasing number of studies have revealed a correlation between tertiary lymphoid structures (TLS) and the outcome of hepatocellular carcinoma (HCC). Nevertheless, the associations between the heterogeneity of cellular composition and the overall survival (OS) in HCC remain unexplored. Herein, we evaluated the cancer tissues from 150 HCC individuals treated at the Tumor Hospital Affiliated with Nantong University using multiplex immunofluorescence to determine the presence and characteristics of TLS and to investigate the relationship between intra-TLS immunologic activity, TLS maturation and intratumoral immune cell infiltration. Prognostic factors influencing the outcome were identified through both univariate and multivariate analyses. Additionally, the levels of cytotoxic T-lymphocyte antigen-4 (CTLA-4), programmed death 1 (PD-1), programmed death-ligand 1 (PD-L1) and lymphocyte activation gene-3 (LAG3) were determined, as well as their relationship with TLS features. TLS was detected in 71 (47.3%) of the 150 HCC cases and was related to higher intratumoral infiltration levels of lymphocytes. Additionally, intra-TLS lymphocyte proliferation correlated with that of intratumoral lymphocytes, and the presence of TLS and a high proportion of mature TLS demonstrated a significant correlation with better prognosis (p=0.013 and p=0.03, respectively). Among TLS-positive tumors, a high proportion of B-cells expressing activation-induced cytidine deaminase (AID) and a high proportion of CD8+ T-cells expressing CD45RO were significantly related to improved OS (p=0.01 and p<0.001, respectively). Comparatively, a high proportion of CD21+CD20+ B-cells demonstrated a significant correlation with poorer OS (p<0.002). A markedly reduced number of CTLA4+ cells in the stromal regions in TLS-negative tumors was observed compared to TLS-positive tumors (p=0.01). These findings reveal a correlation between TLS presence and improved OS in HCC patients. However, TLS exhibited significant variation in maturation state, T and B cell proliferation, and expression of markers related to B and T cell function. Notably, these characteristics were also found to possess prognostic significance, indicating that certain TLS might hinder tumor immunity by inhibiting immune cells while others may foster antigen-driven immune responses, likely influenced by the composition and functional status of intra-TLS lymphocytes.

Tertiary lymphoid structures in anticancer immunity

Tertiary lymphoid structures (TLS) are transient ectopic lymphoid aggregates where adaptive antitumour cellular and humoral responses can be elaborated. Initially described in non-small cell lung cancer as functional immune lymphoid structures associated with better clinical outcome, TLS have also been found in many other carcinomas, as well as melanomas and sarcomas, and associated with improved response to immunotherapy. The manipulation of TLS as a therapeutic strategy is now coming of age owing to the likely role of TLS in the improved survival of patients with cancer receiving immune checkpoint inhibitor treatment. TLS have also garnered considerable interest as a predictive biomarker of the response to antitumour therapies, including immune checkpoint blockade and, possibly, chemotherapy. However, several important questions still remain regarding the definition of TLS in terms of both their cellular composition and functions. Here, we summarize the current views on the composition of TLS at different stages of their development. We also discuss the role of B cells and T cells associated with TLS and their dialogue in mounting antibody and cellular antitumour responses, as well as some of the various mechanisms that negatively regulate antitumour activity of TLS. The prognostic value of TLS to the clinical outcome of patients with cancer and the relationship between TLS and the response to therapy are then addressed. Finally, we present some preclinical evidence that favours the idea that manipulating the formation and function of TLS could lead to a potent next-generation cancer immunotherapy.

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.

Tertiary lymphoid structures and their therapeutic implications in cancer

Tertiary lymphoid structures (TLSs) are ectopic lymphoid aggregates formed by the structured accumulation of immune cells such as B cells and T cells in non-lymphoid tissues induced by infection, inflammation, and tumors. They play a crucial role in the immune response, particularly in association with tumor development, where they primarily exert anti-tumor immune functions during tumorigenesis. Current research suggests that TLSs inhibit tumor growth by facilitating immune cell infiltration and are correlated with favorable prognosis in various solid tumors, serving as an indicator of immunotherapy effectiveness to some extent. Therefore, TLSs hold great promise as a valuable biomarker. Most importantly, immunotherapies aimed to prompting TLSs formation are anticipated to be potent adjuncts to current cancer treatment. This review focuses on the formation process of TLSs and their potential applications in cancer therapy.

A Mature Tertiary Lymphoid Structure with a Ki-67-Positive Proliferating Germinal Center Is Associated with a Good Prognosis and High Intratumoral Immune Cell Infiltration in Advanced Colorectal Cancer

Tertiary lymphoid structures (TLSs) are complex lymphocyte clusters that arise in non-lymphoid tissues due to inflammation or cancer. A mature TLS with proliferating germinal centers is associated with a favorable prognosis in various cancers. However, the effect of TLS maturity on advanced colorectal cancer (CRC) remains unexplored. We analyzed the significance of TLS maturity and tumor Ki-67 expression in surgically resected tumors from 78 patients with pathological T4 CRC. Mature TLS was defined as the organized infiltration of T and B cells with Ki-67-positive proliferating germinal centers. We analyzed the relationship between TLS maturity and intratumoral immune cell infiltration. Mature TLS with germinal center Ki-67 expression was associated with microsatellite instability and improved survival; however, high tumor Ki-67 expression was associated with poor survival in the same cohort. Multivariate analysis identified the absence of mature TLS as an independent predictor of poor post-recurrence overall survival. Intratumoral infiltration of T lymphocytes and macrophages was significantly elevated in tumors with mature TLS compared to those lacking it. High Ki-67 levels and absent mature TLS were identified as poor prognostic factors in advanced CRC. Mature TLS could serve as a promising marker for patients at high-risk of CRC.

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.

Impact of tertiary lymphoid structures on prognosis and therapeutic response in pancreatic ductal adenocarcinoma

BACKGROUND

Pancreatic ductal adenocarcinoma (PDAC) is known to have a heterogeneous desmoplastic tumour microenvironment (TME) with a large number of immunosuppressive cells. Recently, high B-cell infiltration in PDAC has received growing interest as a potential therapeutic target.

METHODS

Our literature review summarises the characteristics of tumour-associated tertiary lymphoid structures (TLSs) and highlight the key studies exploring the clinical outcomes of TLSs in PDAC patients and the direct effect on the TME.

RESULTS

The location, density and maturity stages of TLSs within tumours play a key role in determining the prognosis and is a new emerging target in cancer immunotherapy.

DISCUSSION

TLS development is imperative to improve the prognosis of PDAC patients. In the future, studying the genetics and immune characteristics of tumour infiltrating B cells and TLSs may lead towards enhancing adaptive immunity in PDAC and designing personalised therapies.

Merkel Cell Carcinoma: Integrating Epidemiology, Immunology, and Therapeutic Updates

Merkel cell carcinoma (MCC) is a rare skin cancer characterized by neuroendocrine differentiation. Its carcinogenesis is based either on the integration of the Merkel cell polyomavirus or on ultraviolet (UV) mutagenesis, both of which lead to high immunogenicity either through the expression of viral proteins or neoantigens. Despite this immunogenicity resulting from viral or UV-associated carcinogenesis, it exhibits highly aggressive behavior. However, owing to the rarity of MCC and the lack of epidemiologic registries with detailed clinical data, there is some uncertainty regarding the spontaneous course of the disease. Historically, advanced MCC patients were treated with conventional cytotoxic chemotherapy yielding a median response duration of only 3 months. Starting in 2017, four programmed cell death protein 1 (PD-1)/programmed cell death-ligand 1 (PD-L1) immune checkpoint inhibitors-avelumab, pembrolizumab, nivolumab (utilized in both neoadjuvant and adjuvant settings), and retifanlimab-have demonstrated efficacy in treating patients with disseminated MCC on the basis of prospective clinical trials. However, generating clinical evidence for rare cancers, such as MCC, is challenging owing to difficulties in conducting large-scale trials, resulting in small sample sizes and therefore lacking statistical power. Thus, to comprehensively understand the available clinical evidence on various immunotherapy approaches for MCC, we also delve into the epidemiology and immune biology of this cancer. Nevertheless, while randomized studies directly comparing immune checkpoint inhibitors and chemotherapy in MCC are lacking, immunotherapy shows response rates comparable to those previously reported with chemotherapy but with more enduring responses. Notably, adjuvant nivolumab has proven superiority to the standard-of-care therapy (observation) in the adjuvant setting.

Machine learning-derived immunosenescence index for predicting outcome and drug sensitivity in patients with skin cutaneous melanoma

The functions of immunosenescence are closely related to skin cutaneous melanoma (SKCM). The aim of this study is to uncover the characteristics of immunosenescence index (ISI) to identify novel biomarkers and potential targets for treatment. Firstly, integrated bioinformatics analysis was carried out to identify risk prognostic genes, and their expression and prognostic value were evaluated. Then, we used the computational algorithm to estimate ISI. Finally, the distribution characteristics and clinical significance of ISI in SKCM by using multi-omics analysis. Patients with a lower ISI had a favorable survival rate, lower chromosomal instability, lower somatic copy-number alterations, lower somatic mutations, higher immune infiltration, and sensitive to immunotherapy. The ISI exhibited robust, which was validated in multiple datasets. Besides, the ISI is more effective than other published signatures in predicting survival outcomes for patients with SKCM. Single-cell analysis revealed higher ISI was specifically expressed in monocytes, and correlates with the differentiation fate of monocytes in SKCM. Besides, individuals exhibiting elevated ISI levels could potentially receive advantages from chemotherapy, and promising compounds with the potential to target high ISI were recognized. The ISI model is a valuable tool in categorizing SKCM patients based on their prognosis, gene mutation signatures, and response to immunotherapy.

Tertiary lymphoid structures in cancer: maturation and induction

Tertiary lymphoid structure (TLS) is an ectopic lymphocyte aggregate formed in peripheral non-lymphoid tissues, including inflamed or cancerous tissue. Tumor-associated TLS serves as a prominent center of antigen presentation and adaptive immune activation within the periphery, which has exhibited positive prognostic value in various cancers. In recent years, the concept of maturity regarding TLS has been proposed and mature TLS, characterized by well-developed germinal centers, exhibits a more potent tumor-suppressive capacity with stronger significance. Meanwhile, more and more evidence showed that TLS can be induced by therapeutic interventions during cancer treatments. Thus, the evaluation of TLS maturity and the therapeutic interventions that induce its formation are critical issues in current TLS research. In this review, we aim to provide a comprehensive summary of the existing classifications for TLS maturity and therapeutic strategies capable of inducing its formation in tumors.

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.

Tertiary lymphoid structures and B cells determine clinically relevant T cell phenotypes in ovarian cancer

Intratumoral tertiary lymphoid structures (TLSs) have been associated with improved outcome in various cohorts of patients with cancer, reflecting their contribution to the development of tumor-targeting immunity. Here, we demonstrate that high-grade serous ovarian carcinoma (HGSOC) contains distinct immune aggregates with varying degrees of organization and maturation. Specifically, mature TLSs (mTLS) as forming only in 16% of HGSOCs with relatively elevated tumor mutational burden (TMB) are associated with an increased intratumoral density of CD8+ effector T (TEFF) cells and TIM3+PD1+, hence poorly immune checkpoint inhibitor (ICI)-sensitive, CD8+ T cells. Conversely, CD8+ T cells from immunologically hot tumors like non-small cell lung carcinoma (NSCLC) are enriched in ICI-responsive TCF1+ PD1+ T cells. Spatial B-cell profiling identifies patterns of in situ maturation and differentiation associated with mTLSs. Moreover, B-cell depletion promotes signs of a dysfunctional CD8+ T cell compartment among tumor-infiltrating lymphocytes from freshly isolated HGSOC and NSCLC biopsies. Taken together, our data demonstrate that - at odds with NSCLC - HGSOC is associated with a low density of follicular helper T cells and thus develops a limited number of mTLS that might be insufficient to preserve a ICI-sensitive TCF1+PD1+ CD8+ T cell phenotype. These findings point to key quantitative and qualitative differences between mTLSs in ICI-responsive vs ICI-irresponsive neoplasms that may guide the development of alternative immunotherapies for patients with HGSOC.

Tertiary lymphoid structures in cancer: immune mechanisms and clinical implications

Cancer is a major cause of death globally, and traditional treatments often have limited efficacy and adverse effects. Immunotherapy has shown promise in various malignancies but is less effective in tumors with low immunogenicity or immunosuppressive microenvironment, especially sarcomas. Tertiary lymphoid structures (TLSs) have been associated with a favorable response to immunotherapy and improved survival in cancer patients. However, the immunological mechanisms and clinical significance of TLS in malignant tumors are not fully understood. In this review, we elucidate the composition, neogenesis, and immune characteristics of TLS in tumors, as well as the inflammatory response in cancer development. An in-depth discussion of the unique immune characteristics of TLSs in lung cancer, breast cancer, melanoma, and soft tissue sarcomas will be presented. Additionally, the therapeutic implications of TLS, including its role as a marker of therapeutic response and prognosis, and strategies to promote TLS formation and maturation will be explored. Overall, we aim to provide a comprehensive understanding of the role of TLS in the tumor immune microenvironment and suggest potential interventions for cancer treatment.

Neoadjuvant systemic therapy for hepatocellular carcinoma

Surgical resection and liver transplant remain the only curative therapies for most patients with hepatocellular carcinoma (HCC). Systemic therapy options have typically been ineffective, but recent advances, such as the combination of immune checkpoint inhibitors and targeted therapies, have shown great promise. Neoadjuvant systemic therapy in resectable or locally advanced HCC is under active investigation with encouraging results in small, early-phase trials. Many of these completed and ongoing trials include combinations of systemic therapy (e.g. immune checkpoint inhibitors, tyrosine kinase inhibitors), transarterial therapies, and radiation. Despite early successes, larger trials with evaluation of long-term oncologic outcomes are needed to determine the role of neoadjuvant systemic therapy in patients with HCC who may be eligible for curative intent surgery or transplant.

Image-based multiplex immune profiling of cancer tissues: translational implications. A report of the International Immuno-oncology Biomarker Working Group on Breast Cancer

Recent advances in the field of immuno-oncology have brought transformative changes in the management of cancer patients. The immune profile of tumours has been found to have key value in predicting disease prognosis and treatment response in various cancers. Multiplex immunohistochemistry and immunofluorescence have emerged as potent tools for the simultaneous detection of multiple protein biomarkers in a single tissue section, thereby expanding opportunities for molecular and immune profiling while preserving tissue samples. By establishing the phenotype of individual tumour cells when distributed within a mixed cell population, the identification of clinically relevant biomarkers with high-throughput multiplex immunophenotyping of tumour samples has great potential to guide appropriate treatment choices. Moreover, the emergence of novel multi-marker imaging approaches can now provide unprecedented insights into the tumour microenvironment, including the potential interplay between various cell types. However, there are significant challenges to widespread integration of these technologies in daily research and clinical practice. This review addresses the challenges and potential solutions within a structured framework of action from a regulatory and clinical trial perspective. New developments within the field of immunophenotyping using multiplexed tissue imaging platforms and associated digital pathology are also described, with a specific focus on translational implications across different subtypes of cancer. © 2024 The Authors. The Journal of Pathology published by John Wiley & Sons Ltd on behalf of The Pathological Society of Great Britain and Ireland.

Epigenetic targets to enhance antitumor immune response through the induction of tertiary lymphoid structures

Tertiary lymphoid structures (TLS) are ectopic lymphoid aggregates found in sites of chronic inflammation such as tumors and autoimmune diseases. The discovery that TLS formation at tumor sites correlated with good patient prognosis has triggered extensive research into various techniques to induce their formation at the tumor microenvironment (TME). One strategy is the exogenous induction of specific cytokines and chemokine expression in murine models. However, applying such systemic chemokine expression can result in significant toxicity and damage to healthy tissues. Also, the TLS formed from exogenous chemokine induction is heterogeneous and different from the ones associated with favorable prognosis. Therefore, there is a need to optimize additional approaches like immune cell engineering with lentiviral transduction to improve the TLS formation in vivo. Similarly, the genetic and epigenetic regulation of the different phases of TLS neogenesis are still unknown. Understanding these molecular regulations could help identify novel targets to induce tissue-specific TLS in the TME. This review offers a unique insight into the molecular checkpoints of the different stages and mechanisms involved in TLS formation. This review also highlights potential epigenetic targets to induce TLS neogenesis. The review further explores epigenetic therapies (epi-therapy) and ongoing clinical trials using epi-therapy in cancers. In addition, it builds upon the current knowledge of tools to generate TLS and TLS phenotyping biomarkers with predictive and prognostic clinical potential.

The Emerging Role of Tertiary Lymphoid Structures in Breast Cancer: A Narrative Review

This narrative review aims to clarify the role of tertiary lymphoid structures in breast cancer. We examine their development, composition, and prognostic value, and current ways of recognizing them. A comprehensive literature review was performed using the PubMed/Medline, Scopus, and EMBASE databases. A significant area of interest in breast cancer research involves targeting immune checkpoint molecules, particularly in the triple-negative subtype, where treatment options remain limited. However, existing biomarkers have limitations in accurately predicting treatment response. In this context, tertiary lymphoid structures (TLSs) emerge as a prognostic biomarker and also as a promising predictive marker for response. TLSs are ectopic lymphoid formations or neo-organogenesis that can develop after prolonged exposure to inflammatory signals mediated by chemokines and cytokines. Their presence is inversely correlated with estrogen receptor (ER) and/or progesterone receptor (PR) expression, but positively associated with a higher pathologic complete response rate and improved overall survival. In certain scenarios, TLS-positive tumors were associated with improved outcomes regardless of the presence of PDL-1 (programmed cell death ligand 1) expression or TILs (tumor-infiltrating lymphocytes).

Prognostic value of tertiary lymphoid structures (TLS) in digestive system cancers: a systematic review and meta-analysis

BACKGROUND

Existing literature suggests that tertiary lymphatic structure (TLS) is associated with the progression of cancer. However, the prognostic role of TLS in digestive system cancers remains controversial. This meta-analysis aims to synthesize currently available evidence in the association between TLS and the survival of digestive system cancers.

METHODS

We systematically searched three digital databases (PubMed, Embase, Web of Science) for articles published from database inception to December 23, 2022. Study selection criteria are based on PECO framework: P (population: patients with digestive system cancers), E (exposure: presence of TLS), C (comparator: absence of TLS), O (outcome: overall survival, OS; recurrence-free survival, RFS; disease-free survival, DFS). The Quality in Prognostic Studies (QUIPS) tool was used to assess risk of bias for included studies. The study protocol was registered with PROSPERO (CRD42023416307).

RESULTS

A total of 25 studies with 6910 patients were included into the final meta-analysis. Random-effects models revealed that the absence of TLS was associated with compromised OS, RFS, and DFS of digestive system cancers, with pooled hazard ratios (HRs) of 1.74 (95% CI: 1.50-2.03), 1.96 (95% CI: 1.58-2.44), and 1.81 (95% CI: 1.49-2.19), respectively. Subgroup analyses disclosed a stronger TLS-survival association for pancreatic cancer, compared with other digestive system cancers.

CONCLUSION

TLS may be of prognostic significance for digestive system cancers. More original studies are needed to further corroborate this finding.

Heterogeneity of tertiary lymphoid structures in cancer

The success of immunotherapy approaches, such as immune checkpoint blockade and cellular immunotherapy with genetically modified lymphocytes, has firmly embedded the immune system in the roadmap for combating cancer. Unfortunately, the majority of cancer patients do not yet benefit from these therapeutic approaches, even when the prognostic relevance of the immune response in their tumor entity has been demonstrated. Therefore, there is a justified need to explore new strategies for inducing anti-tumor immunity. The recent connection between the formation of ectopic lymphoid aggregates at tumor sites and patient prognosis, along with an effective anti-tumor response, suggests that manipulating the occurrence of these tertiary lymphoid structures (TLS) may play a critical role in activating the immune system against a growing tumor. However, mechanisms governing TLS formation and a clear understanding of their substantial heterogeneity are still lacking. Here, we briefly summarize the current state of knowledge regarding the mechanisms driving TLS development, outline the impact of TLS heterogeneity on clinical outcomes in cancer patients, and discuss appropriate systems for modeling TLS heterogeneity that may help identify new strategies for inducing protective TLS formation in cancer patients.

Regulation, Maintenance, and Remodeling of High Endothelial Venules in Homeostasis, Inflammation, and Cancer

High endothelial venules (HEVs), high walled cuboidal blood vessels, through their expression of adhesion molecules and chemokines, allow the entrance of lymphoid cells into primary, secondary, and tertiary lymphoid structures (aka tertiary lymphoid organs). HEV heterogeneity exists between various lymphoid organs in their expression of peripheral node addressin (PNAd) and mucosal vascular addressin adhesion molecule 1(MAdCAM-1). Transcriptomic analyses reveal extensive heterogeneity, plasticity, and regulation of HEV gene expression in ontogeny, acute inflammation, and chronic inflammation within and between lymphoid organs. Rules regulating HEV development are flexible in inflammation. HEVs in tumor tertiary lymphoid structures are diagnostic of favorable clinical outcome and response to Immunotherapy, including immune check point blockade. Immunotherapy induces HEVs and provides an entrance for naïve, central memory, and effector cells and a niche for stem like precursor cells. Understanding HEV regulation will permit their exploitation as routes for drug delivery to autoimmune lesions, rejecting organs, and tumors.

B cells and tertiary lymphoid structures are associated with survival in papillary thyroid cancer

PURPOSE

The function of B cells in papillary thyroid cancer (PTC) is controversial. The role of B-cell-related tertiary lymphoid structures (TLSs) is still unclear. Whether B cells exert their anti-tumor effect through forming TLS in PTC needs further investigation.

METHODS

We detected the percentage of B cells in PTC tissues by multi-parameter flow cytometry. Paraffin-embedded tumor tissues of 125 PTC patients were collected and stained with Haematoxylin-Eosin (H&E) for inflammatory infiltration analysis in combination with clinical features. Multiplexed immunohistochemistry (mIHC) was performed to verify the TLSs in above inflammatory infiltration. Correlation of B cells and TLSs with prognosis was analyzed using the TCGA database.

RESULTS

We observed that PTC patients with higher expression of B lineage cell genes had improved survival and the percentage of B cells in the PTC tumor tissues was variable. Moreover, PTC tumor tissues with more B cells were surrounded by immune cell aggregates of varying sizes. We furtherly confirmed the immune cell aggregates as TLSs with different maturation stages. By analyzing PTC data from TCGA database, we found the maturation stages of TLSs were associated with genders and clinical stages among PTC patients. Moreover, patients with high TLSs survived longer and had a better prognosis.

CONCLUSION

B cells are associated with the existence of TLSs which have different maturation stages in PTC. Both B cells and TLSs are associated with the survival rate of PTC. These observations indicate that the anti-tumor effects of B cells in PTC are associated with TLSs formation.

Association of NRAS mutations and tertiary lymphoid structure formation with clinical outcomes of adjuvant PD-1 inhibitors for acral melanoma

OBJECTIVES

This study evaluates the efficacy of programmed death-1 (PD-1) inhibitors as adjuvant therapy for acral melanoma (AM) and the predictive value of genetic mutations and tertiary lymphoid structures (TLSs).

METHODS AND RESULTS

A single-center retrospective longitudinal cohort study was conducted between October 1, 2018, and September 31, 2022. Patients with stages II-III completely resected AM were treated with at least two doses of adjuvant PD-1 inhibitors. A total of 44 participants were included in the final analysis, of which 41 patients with stage III. The median follow-up time, median relapse-free survival (RFS), and median distance metastasis-free survival (DMFS) for all patients were 18.4 months, 21.6 months, and 30.6 months, respectively. 21 (47.7%) and 20 (45.5%) patients were intravenously administered pembrolizumab and toripalimab, respectively. There were no significant differences in RFS (24.4 months vs. 18.9 months, p = 0.432) or DMFS (30.6 months vs. not reached, p = 0.865) between the pembrolizumab and toripalimab groups, respectively. The median DMFS (41.1 months vs. 9.0 months, p < 0.001) in the wild-type NRAS group was significantly longer than that in the NRAS mutation group. Overall, different levels of TLSs infiltration did not significantly affect patient survival. Only three people discontinued treatment due to adverse events. No treatment-related death occurred during the study period.

CONCLUSION

Our study suggests that adjuvant toripalimab and pembrolizumab therapy have comparable efficacies in patients with AM and are both well tolerated. Adjuvant monotherapy with PD-1 inhibitors may not be appropriate for AM with NRAS mutations.

Of mice and lymphoid aggregates: modeling tertiary lymphoid structures in cancer

Tertiary lymphoid structures (TLS) are lymph node-like aggregates that can form in association with chronic inflammation or cancer. Mature TLS are organized into B and T cell zones, and are not encapsulated but include all cell types necessary for eliciting an adaptive immune response. TLS have been observed in various cancer types and are generally associated with a positive prognosis as well as increased sensitivity to cancer immunotherapy. However, a comprehensive understanding of the roles of TLS in eliciting anti-tumor immunity as well as the mechanisms involved in their formation and function is still lacking. Further studies in orthotopic, immunocompetent cancer models are necessary to evaluate the influence of TLS on cancer therapies, and to develop new treatments that promote their formation in cancer. Here, we review key insights obtained from functional murine studies, discuss appropriate models that can be used to study cancer-associated TLS, and suggest guidelines on how to identify TLS and distinguish them from other antigen-presenting niches.

An update on methods for detection of prognostic and predictive biomarkers in melanoma

The approval of immunotherapy for stage II-IV melanoma has underscored the need for improved immune-based predictive and prognostic biomarkers. For resectable stage II-III patients, adjuvant immunotherapy has proven clinical benefit, yet many patients experience significant adverse events and may not require therapy. In the metastatic setting, single agent immunotherapy cures many patients but, in some cases, more intensive combination therapies against specific molecular targets are required. Therefore, the establishment of additional biomarkers to determine a patient's disease outcome (i.e., prognostic) or response to treatment (i.e., predictive) is of utmost importance. Multiple methods ranging from gene expression profiling of bulk tissue, to spatial transcriptomics of single cells and artificial intelligence-based image analysis have been utilized to better characterize the immune microenvironment in melanoma to provide novel predictive and prognostic biomarkers. In this review, we will highlight the different techniques currently under investigation for the detection of prognostic and predictive immune biomarkers in melanoma.

Mature tertiary lymphoid structures are key niches of tumour-specific immune responses in pancreatic ductal adenocarcinomas

OBJECTIVE

To better understand the immune microenvironment of pancreatic ductal adenocarcinomas (PDACs), here we explored the relevance of T and B cell compartmentalisation into tertiary lymphoid structures (TLSs) for the generation of local antitumour immunity.

DESIGN

We characterised the functional states and spatial organisation of PDAC-infiltrating T and B cells using single-cell RNA sequencing (scRNA-seq), flow cytometry, multicolour immunofluorescence, gene expression profiling of microdissected TLSs, as well as in vitro assays. In addition, we performed a pan-cancer analysis of tumour-infiltrating T cells using scRNA-seq and sc T cell receptor sequencing datasets from eight cancer types. To evaluate the clinical relevance of our findings, we used PDAC bulk RNA-seq data from The Cancer Genome Atlas and the PRINCE chemoimmunotherapy trial.

RESULTS

We found that a subset of PDACs harbours fully developed TLSs where B cells proliferate and differentiate into plasma cells. These mature TLSs also support T cell activity and are enriched with tumour-reactive T cells. Importantly, we showed that chronically activated, tumour-reactive T cells exposed to fibroblast-derived TGF-β may act as TLS organisers by producing the B cell chemoattractant CXCL13. Identification of highly similar subsets of clonally expanded CXCL13 + tumour-infiltrating T cells across multiple cancer types further indicated a conserved link between tumour-antigen recognition and the allocation of B cells within sheltered hubs in the tumour microenvironment. Finally, we showed that the expression of a gene signature reflecting mature TLSs was enriched in pretreatment biopsies from PDAC patients with longer survival after receiving different chemoimmunotherapy regimens.

CONCLUSION

We provided a framework for understanding the biological role of PDAC-associated TLSs and revealed their potential to guide the selection of patients for future immunotherapy trials.

Tertiary Lymphoid Structures Are Related to Inflammatory Progression and Bone Loss in Human Apical Periodontitis

INTRODUCTION

Bone loss is strongly associated with the immunologic milieu in apical periodontitis (AP). Tertiary lymphoid structures (TLSs) are organized lymphoid cell aggregates that form in nonlymphoid tissues under persistent inflammatory circumstances. To date, there has been no relevant report of TLSs in periapical lesions. This work aimed to investigate the formation and potential function of TLSs in AP.

METHODS

Tissues from human apical lesions (n = 61) and healthy oral mucosa (n = 5) were collected. Immunohistochemistry and multiplex immunofluorescence were used to detect the formation of TLSs. Correlation analyses were performed between clinical variables and TLSs. In addition, immunohistochemistry was used to evaluate the expression of interleukin-1 beta, interleukin-6, receptor activator of nuclear factor kappa-B ligand, and macrophage subsets in the apical lesions.

RESULTS

Periapical granulomas (n = 24) and cysts (n = 37) were identified by histologic evaluation. TLSs, composed of B-cell and T-cell clusters, developed in periapical granulomas and radicular cysts. The CXC-chemokine ligand 13, its receptor CXC-chemokine receptor 5, follicular dendritic cells, and high endothelial venules were localized in TLSs. The quantity and size of TLSs were positively associated with bone loss in AP. Moreover, proinflammatory cytokines and macrophage subsets were also substantially elevated in TLS regions of apical lesions.

CONCLUSIONS

The formation of TLSs in periapical granulomas and cysts was closely associated with persistent immune responses and bone loss in apical lesions. TLSs provide an updated insight into the complicated immune response process in AP.

Harnessing the power of oncolytic virotherapy and tertiary lymphoid structures to amplify antitumor immune responses in cancer patients

Tertiary lymphoid structures (TLS) are ectopic aggregates of immune cells that develop in non-lymphoid tissues under persistent inflammation. Since their presence has been associated with a better prognosis in cancer patients, modulating TLS formation is being part of new challenges in immunotherapy. Although mechanisms underlying TLS genesis are still not fully understood, different strategies have been developed in preclinical models to induce their formation and ultimately enhance antitumor responses. Herein, we will discuss a new approach that would consist in using oncolytic viruses (OV). These viruses have the unique feature to preferentially infect, replicate in and kill cancer cells. Their immunoadjuvant property, their use as a vector of therapeutic molecules and their selectivity for cancer cells, make them an attractive strategy to induce TLS in the tumor microenvironment. This review will examine the current knowledge about TLS neogenesis, approaches for inducing them, and relevance of using OV for this purpose, especially in combination with immunotherapy such as immune checkpoint blockade.

Single-cell transcriptome sequencing of B-cell heterogeneity and tertiary lymphoid structure predicts breast cancer prognosis and neoadjuvant therapy efficacy

BACKGROUND

Breast cancer (BC) is a highly heterogeneous disease, and although immunotherapy has recently increased patient survival in a number of solid and hematologic malignancies, most BC subtypes respond poorly to immune checkpoint blockade therapy (ICB). B cells, particularly those that congregate in tertiary lymphoid structures (TLS), play a significant role in antitumour immunity. However, B-cell heterogeneity at single-cell resolution and its clinical significance with TLS in BC need to be explored further.

METHODS

Primary tumour lesions and surrounding normal tissues were taken from 14 BC patients, totaling 124,587 cells, for single-cell transcriptome sequencing and bioinformatics analysis.

RESULTS

Based on the usual markers, the single-cell transcriptome profiles were classified into various clusters. A thorough single-cell study was conducted with a focus on tumour-infiltrating B cells (TIL-B) and tumour-associated neutrophils (TAN). TIL-B was divided into five clusters, and unusual cell types, such as follicular B cells, which are strongly related to immunotherapy efficacy, were identified. In BC, TAN and TIL-B infiltration are positively correlated, and at the same time, compared with TLS-high, TAN and TIL-B in TLS-low group are significantly positively correlated.

CONCLUSIONS

In conclusion, our study highlights the heterogeneity of B cells in BC, explains how B cells and TLS contribute significantly to antitumour immunity at both the single-cell and clinical level, and offers a straightforward marker for TLS called CD23. These results will offer more pertinent information on the applicability and effectiveness of tumour immunotherapy for BC.

Expression of lymphoid structure-associated cytokine/chemokine gene transcripts in tumor and protein in serum are prognostic of melanoma patient outcomes

Background

Proinflammatory chemokines/cytokines support development and maturation of tertiary lymphoid structures (TLS) within the tumor microenvironment (TME). In the current study, we sought to investigate the prognostic value of TLS-associated chemokines/cytokines (TLS-kines) expression levels in melanoma patients by performing serum protein and tissue transcriptomic analyses, and to then correlate these data with patients clinicopathological and TME characteristics.

Methods

Levels of TLS-kines in patients' sera were quantitated using a custom Luminex Multiplex Assay. The Cancer Genomic Atlas melanoma cohort (TCGA-SKCM) and a Moffitt Melanoma cohort were used for tissue transcriptomic analyses. Associations between target analytes and survival outcomes, clinicopathological variables, and correlations between TLS-kines were statistically analyzed.

Results

Serum of 95 patients with melanoma were evaluated; 48 (50%) female, median age of 63, IQR 51-70 years. Serum levels of APRIL/TNFSF13 were positively correlated with levels of both CXCL10 and CXCL13. In multivariate analyses, high levels of serum APRIL/TNFSF13 were associated with improved event-free survival after adjusting for age and stage (HR = 0.64, 95% CI 0.43-0.95; p = 0.03). High expression of APRIL/TNFSF13 tumor transcripts was significantly associated with improved OS in TCGA-SKCM (HR = 0.69, 95% CI 0.52-0.93; p = 0.01) and in Moffitt Melanoma patients (HR = 0.51, 95% CI: 0.32-0.82; p = 0.006). Further incorporation of CXCL13 and CXCL10 tumor transcript levels in a 3-gene index revealed that high APRIL/CXCL10/CXCL13 expression was associated with improved OS in the TCGA SKCM cohort (HR = 0.42, 95% CI 0.19-0.94; p = 0.035). Melanoma differentially expressed genes positively associated with high APRIL/CXCL10/CXCL13 tumor expression were linked to tumor infiltration by a diverse array of proinflammatory immune cell types.

Conclusion

Serum protein and tumor transcript levels of APRIL/TNFSF13 are associated with improved survival outcomes. Patients exhibiting high coordinate expression of APRIL/CXCL10/CXCL13 transcripts in their tumors displayed superior OS. Further investigation of TLS-kine expression profiles related to clinical outcomes in larger cohort studies is warranted.

Immune-checkpoint inhibitor resistance in cancer treatment: Current progress and future directions

Cancer treatment has been advanced with the advent of immune checkpoint inhibitors (ICIs) exemplified by anti-cytotoxic T-lymphocyte-associated protein 4 (CTLA-4), anti-programmed cell death protein 1 (PD-1) and programmed cell death ligand 1 (PD-L1) drugs. Patients have reaped substantial benefit from ICIs in many cancer types. However, few patients benefit from ICIs whereas the vast majority undergoing these treatments do not obtain survival benefit. Even for patients with initial responses, they may encounter drug resistance in their subsequent treatments, which limits the efficacy of ICIs. Therefore, a deepening understanding of drug resistance is critically important for the explorations of approaches to reverse drug resistance and to boost ICI efficacy. In the present review, different mechanisms of ICI resistance have been summarized according to the tumor intrinsic, tumor microenvironment (TME) and host classifications. We further elaborated corresponding strategies to battle against such resistance accordingly, which include targeting defects in antigen presentation, dysregulated interferon-γ (IFN-γ) signaling, neoantigen depletion, upregulation of other T cell checkpoints as well as immunosuppression and exclusion mediated by TME. Moreover, regarding the host, several additional approaches that interfere with diet and gut microbiome have also been described in reversing ICI resistance. Additionally, we provide an overall glimpse into the ongoing clinical trials that utilize these mechanisms to overcome ICI resistance. Finally, we summarize the challenges and opportunities that needs to be addressed in the investigation of ICI resistance mechanisms, with the aim to benefit more patients with cancer.

Barriers to immune cell infiltration in tumors

Increased immune cell infiltration into tumors is associated with improved patient survival and predicts response to immune therapies. Thus, identification of factors that determine the extent of immune infiltration is crucial, so that methods to intervene on these targets can be developed. T cells enter tumor tissues through the vasculature, and under control of interactions between homing receptors on the T cells and homing receptor ligands (HRLs) expressed by tumor vascular endothelium and tumor cell nests. HRLs are often deficient in tumors, and there also may be active barriers to infiltration. These remain understudied but may be crucial for enhancing immune-mediated cancer control. Multiple intratumoral and systemic therapeutic approaches show promise to enhance T cell infiltration, including both approved therapies and experimental therapies. This review highlights the intracellular and extracellular determinants of immune cell infiltration into tumors, barriers to infiltration, and approaches for intervention to enhance infiltration and response to immune therapies.

B cells in the tumor microenvironment: Multi-faceted organizers, regulators, and effectors of anti-tumor immunity

Our understanding of tumor-infiltrating lymphocytes (TILs) is rapidly expanding beyond T cell-centric perspectives to include B cells and plasma cells, collectively referred to as TIL-Bs. In many cancers, TIL-Bs carry strong prognostic significance and are emerging as key predictors of response to immune checkpoint inhibitors. TIL-Bs can perform multiple functions, including antigen presentation and antibody production, which allow them to focus immune responses on cognate antigen to support both T cell responses and innate mechanisms involving complement, macrophages, and natural killer cells. In the stroma of the most immunologically "hot" tumors, TIL-Bs are prominent components of tertiary lymphoid structures, which resemble lymph nodes structurally and functionally. Additionally, TIL-Bs participate in a variety of other lympho-myeloid aggregates and engage in dynamic interactions with the tumor stroma. Here, we summarize our current understanding of TIL-Bs in human cancer, highlighting the compelling therapeutic opportunities offered by their unique tumor recognition and effector mechanisms.

Tertiary lymphoid structures in head and neck squamous cell carcinoma improve prognosis by recruiting CD8+ T cells

Tertiary lymphoid structures (TLSs) are formed in long-term chronic inflammation, promoting the local recruitment of lymphocytes, antigen presentation and regulation of immune response, correlated with a better prognosis for cancer patients. Although studies have been conducted to explore methods that accelerate the establishment of TLSs, related research in head and neck squamous cell carcinoma (HNSCC) is still lacking. In this study, we analysed data from The Cancer Genome Atlas and performed immunohistochemical staining analyses of 188 patient samples. The results showed that TLSs promoted the infiltration of immune cells. Patients with TLSs with high infiltration of CD8⁺ cells showed the best prognosis. Since lymphotoxin α (LTα) was significantly increased in tissues with TLSs, we overexpressed LTα in SCC7 cells (a mouse-derived HNSCC cell line) and established tongue-tumour-bearing models. The polychromatic observation of tissue sections showed that T-cell aggregation increased in the LTα cell group, and a grade 1 TLS was formed on the 12th day after inoculating the cells. Moreover, the tumour volume in the LTα group was significantly less than that of the control group, whereas both the number and the proportion of infiltrated CD8⁺ T cells were increased. The peripheral CD8⁺ cells in mice were removed, and no difference was observed in tumour size or TLS formation. Remarkably, we found that TLS led to an increase in the antitumour effect by recruiting CD8⁺ T cells in HNSCC, showing a CD8⁺ T-cell-dependent antitumour effect. Moreover, LTα overexpression in the tumour promoted the formation of TLSs.

Tertiary lymphoid structures in desmoplastic melanoma have increased lymphocyte density, lymphocyte proliferation, and immune cross talk with tumor when compared to non-desmoplastic melanomas

Tertiary lymphoid structures (TLS) are ectopic lymphoid structures that can arise in human cancers and are associated with improved overall survival (OS) and response to immune checkpoint blockade (ICB) in several cancers, including non-desmoplastic metastatic melanoma (NDMM). Desmoplastic melanoma (DM) has one of the highest response rates to ICB, and we previously identified that primary DM (PDM) contains TLS. Despite the association of TLS with survival and ICB response, it is unknown whether TLS or associated markers of immune activity can differ between PDM and NDMM. We hypothesized that PDM would contain higher frequencies of TLS than NDMM, that T and B-cell densities and proliferation would be greater in TLS of PDM than TLS of NDMM, and that proliferation rates of T and B-cells in PDM TLS would be concordant with those of intratumoral lymphocytes. We found that four features of TLS in PDM distinguish them from TLS in NDMM. TLS were peritumoral in NDMM but intratumoral in PDM. CD8⁺ T-cell and CD20⁺ B-cell densities and proliferative fractions were higher in PDM TLS than NDMM TLS. Additionally, the proliferative fractions of T- and B-cells were concordant between the TLS and tumor site in PDM and discordant in NDMM. Collectively, these data suggest that TLS and associated immune markers can differ across melanoma subsets and suggest that PDM TLS may be more immunologically active and have enhanced immune cell trafficking between tumor and TLS compared to NDMM.

Tertiary Lymphoid Structures: A Potential Biomarker for Anti-Cancer Therapy

A tertiary lymphoid structure (TLS) is a special component in the immune microenvironment that is mainly composed of tumor-infiltrating lymphocytes (TILs), including T cells, B cells, DC cells, and high endothelial venules (HEVs). For cancer patients, evaluation of the immune microenvironment has a predictive effect on tumor biological behavior, treatment methods, and prognosis. As a result, TLSs have begun to attract the attention of researchers as a new potential biomarker. However, the composition and mechanisms of TLSs are still unclear, and clinical detection methods are still being explored. Although some meaningful results have been obtained in clinical trials, there is still a long way to go before such methods can be applied in clinical practice. However, we believe that with the continuous progress of basic research and clinical trials, TLS detection and related treatment can benefit more and more patients. In this review, we generalize the definition and composition of TLSs, summarize clinical trials involving TLSs according to treatment methods, and describe possible methods of inducing TLS formation.

CD103 and periplakin are potential biomarkers for response of metastatic melanoma to pembrolizumab

This study was designed to screen for preliminary evidence of predictive markers of melanoma response to PD-1 blockade. We hypothesized that the following immune markers would be positive predictors of response: increased densities of CD103 + CD8 + T cells or Th1 lineage T-bet + T cells, high expression of CXCL9-11 and presence of tertiary lymphoid structures. Conversely, we hypothesized that the high expression of barrier molecules would be a negative predictor of response. Patients with advanced melanoma treated with pembrolizumab were identified, and clinical response as well as overall survival data were collected. Tumor samples were evaluated by multiplex immunofluorescence histology. All statistical analyses were performed in R Studio and Microsoft Excel using the Mann-Whitney U test, chi-square test, Spearman's rank correlation and Kaplan-Meier survival curves. Sixty-five advanced melanoma patients were identified, of whom 46 met inclusion criteria and were included in this study. Increased densities ( P  = 0.04) and proportions ( P  = 0.02) of CD8 + T cells expressing CD103 + were associated with complete response (CR) to pembrolizumab. Improved survival was associated with increased proportions of CD8 + cells expressing CD103 ( P  = 0.0085) as well as decreased density of periplakin + cells ( P  = 0.012) and periplakin + SOX10 + cells ( P  = 0.0012). The density and proportion of CD8 + T cells expressing CD103 + positively correlated with PD-L1 expression, though PD-L1 expression was not significantly correlated with outcomes. This screening study found that increased density and proportion of CD8 + T cells expressing CD103 and decreased density of periplakin were associated with positive outcomes in patients with melanoma metastases treated with pembrolizumab and may warrant further study.

[Melanoma microenvironment-impact of modern therapies]

BACKGROUND

A considerable proportion of patients with advanced melanoma succumb to metastatic disease despite the initial success of modern therapies.

OBJECTIVES

An overview of the melanoma tumor microenvironment with special focus on approved therapies and new innovative strategies is given.

METHODS

Current clinical trials and scientific insights concerning the impact of the tumor microenvironment on progression and therapy of advanced melanoma are reviewed and discussed.

RESULTS

The tumor microenvironment with its manifold components and interactions plays a major role in the treatment of malignant melanoma.

CONCLUSION

Innovative new strategies that target an immunosuppressive microenvironment may improve the therapeutic efficacy of current treatment of advanced melanoma.

Tertiary lymphoid structures accompanied by fibrillary matrix morphology impact anti-tumor immunity in basal cell carcinomas

Tertiary lymphoid structures (TLS) are specialized lymphoid formations that serve as local repertoire of T- and B-cells at sites of chronic inflammation, autoimmunity, and cancer. While presence of TLS has been associated with improved response to immune checkpoint blockade therapies and overall outcomes in several cancers, its prognostic value in basal cell carcinoma (BCC) has not been investigated. Herein, we determined the prognostic impact of TLS by relating its prevalence and maturation with outcome measures of anti-tumor immunity, namely tumor infiltrating lymphocytes (TILs) and tumor killing. In 30 distinct BCCs, we show the presence of TLS was significantly enriched in tumors harboring a nodular component and more mature primary TLS was associated with TIL counts. Moreover, assessment of the fibrillary matrix surrounding tumors showed discrete morphologies significantly associated with higher TIL counts, critically accounting for heterogeneity in TIL count distribution within TLS maturation stages. Specifically, increased length of fibers and lacunarity of the matrix with concomitant reduction in density and alignment of fibers were present surrounding tumors displaying high TIL counts. Given the interest in inducing TLS formation as a therapeutic intervention as well as its documented prognostic value, elucidating potential impediments to the ability of TLS in driving anti-tumor immunity within the tumor microenvironment warrants further investigation. These results begin to address and highlight the need to integrate stromal features which may present a hindrance to TLS formation and/or effective function as a mediator of immunotherapy response.

The prognostic value and molecular properties of tertiary lymphoid structures in oesophageal squamous cell carcinoma

BACKGROUND

Tertiary lymphoid structures (TLSs) play key roles in tumour adaptive immunity. However, the prognostic value and molecular properties of TLSs in oesophageal squamous cell carcinoma (ESCC) patients have not been studied.

METHODS

The prognostic values of the presence and maturation status of tumour-associated TLSs were determined in 394 and 256 ESCC patients from Sun Yat-sen University Cancer Center (Centre A) and the Cancer Hospital of Shantou University Medical College (Centre B), respectively. A deep-learning (DL) TLS classifier was established with haematoxylin and eosin (H&E)-stained slides using an inception-resnet-v2 neural network. Digital spatial profiling was performed to determine the cellular and molecular properties of TLSs in ESCC tissues.

RESULTS

TLSs were observed in 73.1% of ESCCs from Centre A via pathological examination of H&E-stained primary tumour slides, among which 42.9% were TLS-mature and 30.2% were TLS-immature tumours. The established DL TLS classifier yielded favourable sensitivities and specificities for patient TLS identification and maturation evaluation, with which 55.1%, 39.5% and 5.5% of ESCCs from Centre B were identified as TLS-mature, TLS-immature and TLS-negative tumours. Multivariate analyses proved that the presence of mature TLSs was an independent prognostic factor in both the Centre A and Centre B cohorts (p < .05). Increased proportions of proliferative B, plasma and CD4+ T helper (Th) cells and increased B memory and Th17 signatures were observed in mature TLSs compared to immature ones. Intratumoural CD8+ T infiltration was increased in TLS-mature ESCC tissues compared to mature TLS-absent tissues. The combination of mature TLS presence and high CD8+ T infiltration was associated with the best survival in ESCC patients.

CONCLUSIONS

Mature TLSs improve the prognosis of ESCC patients who underwent complete resection. The use of the DL TLS classifier would facilitate precise and efficient evaluation of TLS maturation status and offer a novel probability of ESCC treatment individualization.

Spatial biology analysis reveals B cell follicles in secondary lymphoid structures may regulate anti-tumor responses at initial melanoma diagnosis

Introduction

B cells are key regulators of immune responses in melanoma. We aimed to explore differences in the histologic location and activation status of B cell follicles in sentinel lymph nodes (SLN) of melanoma patients.

Methods

Flow cytometry was performed on fresh tumor draining lymph nodes (LN). Paraffin slides from a separate cohort underwent NanoString Digital Spatial Profiling (DSP)®. After staining with fluorescent markers for CD20 (B cells), CD3 (T cells), CD11c (antigen presenting cells) and a nuclear marker (tumor) was performed, regions of interest (ROI) were selected based on the location of B cell regions (B cell follicles). A panel of 68 proteins was then analyzed from the ROIs.

Results

B cell percentage trended higher in patients with tumor in LN (n=3) compared to patients with nSLN (n=10) by flow cytometry. B cell regions from a separate cohort of patients with tumor in the (pSLN) (n=8) vs. no tumor (nSLN) (n=16) were examined with DSP. Within B cell regions of the SLN, patients with pSLN had significantly higher expression of multiple activation markers including Ki-67 compared to nSLN patients. Among 4 patients with pSLN, we noted variability in arrangement of B cell follicles which were either surrounding the tumor deposit or appeared to be infiltrating the tumor. The B cell follicle infiltrative pattern was associated with prolonged recurrence free survival.

Conclusion

These data suggest a role for B cell follicles in coordinating effective adaptive immune responses in melanoma when low volume metastatic disease is present in tumor draining LN.

Tertiary Lymphoid Structures as Mediators of Immunotherapy Response

Simple Summary

Tertiary lymphoid structures (TLS) are anatomic entities that are similar to, but distinct from, secondary lymphoid structures (e.g., lymph nodes) that allow for a host’s own immune system to respond in a more targeted and efficacious way. TLS are increasingly recognized as markers of prognosis in cancer patients and are now being implicated as direct mediators of immunotherapy efficacy. The inherent properties of TLS, as well as their cellular constituents, are being elucidated across tumor types, with commonalities becoming more apparent. Given the importance of TLS in a patient’s response to malignancy, the ability to induce TLS promises to be an advantageous therapeutic avenue and already appears feasible in preclinical models.

Abstract

Since its first application in the treatment of cancer during the 1800s, immunotherapy has more recently become the leading edge of novel treatment strategies. Even though the efficacy of these agents can at times be predicted by more traditional metrics and biomarkers, often patient responses are variable. TLS are distinct immunologic structures that have been identified on pathologic review of various malignancies and are emerging as important determinants of patient outcome. Their presence, location, composition, and maturity are critically important in a host’s response to malignancy. Because of their unique immunogenic niche, they are also prime candidates, not only to predict and measure the efficacy of immunotherapy agents, but also to be potentially inducible gatekeepers to increase therapeutic efficacy. Herein, we review the mechanistic underpinnings of TLS formation, the data on its relationship to various malignancies, and the emerging evidence for the role of TLS in immunotherapy function.

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.

Tertiary Lymphatic Structures in Primary Hepatic Carcinoma: Controversy Cannot Overshadow Hope

Tertiary lymphoid structures (TLSs) are organized aggregates of immune cells found in the tumor microenvironment. TLS can influence primary hepatic carcinoma (PHC) occurrence and have an active role in cancer. TLS can promote or inhibit the growth of PHC depending on their location, and although available findings are controversial, they suggest that TLS have a protective role in PHC tissues and a non-protective role in paracancerous tissues. In addition, the cellular composition of TLS can also influence the outcome of PHC. As an immunity marker, TLS can act as a marker of immunotherapy to predict its effect and help to identify patients who will respond well to immunotherapy. Modulation of TLS formation through the use of chemokines/cytokines, immunotherapy, or induction of high endothelial vein to interfere with tumor growth has been studied extensively in PHC and other cancers. In addition, new tools such as genetic interventions, cellular crosstalk, preoperative radiotherapy, and advances in materials science have been shown to influence the prognosis of malignant tumors by modulating TLS production. These can also be used to develop PHC treatment.

The vaccine-site microenvironment: impacts of antigen, adjuvant, and same-site vaccination on antigen presentation and immune signaling

Background

A goal of cancer vaccines is to induce strong T cell responses to tumor antigens, but the delivery method, schedule, and formulation of cancer vaccines have not yet been optimized. Adjuvants serve to increase the immune response against vaccine antigens. However, little is known about the impact of adjuvants plus antigen and their delivery schedule on the immunologic milieu in the vaccine-site microenvironment (VSME). We hypothesized that antigen processing and presentation may occur directly in the VSME, that adding the toll-like receptor 3 (TLR3) agonist polyICLC (pICLC) would enhance markers of immune activation, and that the immune signatures would be enhanced further by repeated vaccination in the same skin site rather than after multiple vaccines in different skin locations.

Methods

Using RNA sequencing, we evaluated VSME biopsies from patients undergoing subcutaneous/intradermal peptide vaccination against melanoma, with incomplete Freund’s adjuvant (IFA) with or without pICLC. Differential gene expression analyses and gene set enrichment analyses were performed using R. False discovery rate corrected p values <0.05 were considered significant.

Results

We found that addition of peptide antigens to IFA enhanced antigen presentation pathways and a tertiary lymphoid structure gene-signature locally at the VSME. Addition of pICLC to IFA + peptide induced an immunologically favorable VSME 1 week after injection but had little impact on the VSME after three injections, compared with IFA + peptide alone. Repeated same-site injection of IFA + peptide antigens induced a VSME with more dendritic cell activation, Th1 dominance, and TLR adaptor protein gene expression than that induced by injections at different, rotating skin locations.

Conclusions

These data suggest that the vaccine-site itself may be a critically important location contributing to vaccine immunity rather than just the draining lymph node, that IFA induces a favorable VSME with TLR agonist being most beneficial early in the vaccine course, and that same-site injections lead to persistent stimulation of immune pathways that may be beneficial in eliciting antigen specific T cell expansion.

Patterns of Tumor Infiltrating Lymphocytes in Adenoid Cystic Carcinoma of the Head and Neck

Simple Summary

Adenoid cystic carcinoma (ACC) is a rare tumor with late occurring metastases and recurrences, which makes it necessary for patients to be monitored closely even beyond the usual five years. So far, there is hardly any effective treatment in the palliative situation and trials on immunotherapeutic drugs have not been successful. We sought to find possible prognostic markers by analyzing patterns of tumor infiltrating immune cells and additionally to learn more about possible reasons for this lack of response to immunotherapy. It appears from our data that it is not relevant for prognosis if the tumor is infiltrated by immune cells. This might also be the reason that immunotherapies do not work in this particular disease, which suggests that ACC is not recognized by infiltrating immune cells. Therefore, the tumor would have to be made visible to the immune system, for example, through vaccinations.

Abstract

Adenoid cystic carcinoma (ACC) is a rare malignancy in the head and neck. The prognosis remains poor and late recurrences often occur after 5 years and later. To date, there are no reliable prognostic markers for ACC. In several solid tumors, tertiary lymphoid structures (TLS) are associated with improved survival. This study aims to investigate the role of distribution patterns of tumor infiltrating immune cells (TIL) in ACC. A cohort of 50 patients from three different cancer centers was available for analysis. Sections were stained for CD3, CD4, CD8 and CD20 and evaluated with regard to their distribution of TIL. Patterns were determined as infiltrated-excluded, infiltrated-inflamed and presence of tertiary lymphoid structures. About half of the cases showed an infiltrated-excluded TIL pattern and only a minority of six cases had TLS present within the tumor. Within the inflamed phenotype CD3+ cells were by far the most abundant lymphocyte subtype, and within this compartment, CD8+ T cells were predominant. There was no influence on overall or disease-free survival by any of the TIL patterns. This indicates that ACC is a tumor with very low immunogenicity and even abundance of lymphocytes does not seem to improve prognosis for this disease. Therefore, the observed lack of response towards immunotherapy is not surprising and other methods to induce recognition of ACC by the immune system must be found.

The Tumor Immune Landscape and Architecture of Tertiary Lymphoid Structures in Urothelial Cancer

Candidate immune biomarkers have been proposed for predicting response to immunotherapy in urothelial cancer (UC). Yet, these biomarkers are imperfect and lack predictive power. A comprehensive overview of the tumor immune contexture, including Tertiary Lymphoid structures (TLS), is needed to better understand the immunotherapy response in UC. We analyzed tumor sections by quantitative multiplex immunofluorescence to characterize immune cell subsets in various tumor compartments in tumors without pretreatment and tumors exposed to preoperative anti-PD1/CTLA-4 checkpoint inhibitors (NABUCCO trial). Pronounced immune cell presence was found in UC invasive margins compared to tumor and stroma regions. CD8⁺PD1⁺ T-cells were present in UC, particularly following immunotherapy. The cellular composition of TLS was assessed by multiplex immunofluorescence (CD3, CD8, FoxP3, CD68, CD20, PanCK, DAPI) to explore specific TLS clusters based on varying immune subset densities. Using a k-means clustering algorithm, we found five distinct cellular composition clusters. Tumors unresponsive to anti-PD-1/CTLA-4 immunotherapy showed enrichment of a FoxP3⁺ T-cell-low TLS cluster after treatment. Additionally, cluster 5 (macrophage low) TLS were significantly higher after pre-operative immunotherapy, compared to untreated tumors. We also compared the immune cell composition and maturation stages between superficial (submucosal) and deeper TLS, revealing that superficial TLS had more pronounced T-helper cells and enrichment of early TLS than TLS located in deeper tissue. Furthermore, superficial TLS displayed a lower fraction of secondary follicle like TLS than deeper TLS. Taken together, our results provide a detailed quantitative overview of the tumor immune landscape in UC, which can provide a basis for further studies.

Tertiary lymphoid structure stratifies glioma into three distinct tumor subtypes

OBJECTIVE

Tertiary lymphoid structure (TLS), also known as ectopic lymphoid organs, are found in cancer, chronic inflammation, and autoimmune diseases. However, the heterogeneity of TLS in gliomas is unclear. Therefore, it is necessary to identify TLS differences and define TLS subtypes.

METHODS

The TLS gene profile of 697 gliomas from The Cancer Genome Atlas (TCGA) was used for consensus clustering to identify robust clusters, and the reproducibility of the stratification method was assessed in Chinese Glioma Genome Atlas (CGGA) cohort1, CGGA_cohort2, and GSE16011. Analyses of clinical characteristics, immune infiltration, and potential biological functions were performed for each subtype.

RESULTS

Three resulting clusters (A, B, and C) were identified based on consensus clustering on the gene expression profile of TLS genes. There was a significant prognostic difference among the clusters, with a shorter survival for C than B and A. In comparison with the A and B subtypes, the C subtype was significantly enriched in primary immunodeficiency, intestinal immune network for lgG production, antigen processing and presentation, natural killer cell-mediated cytotoxicity, complement and coagulation cascades, cytokine-cytokine receptor interaction, leukocyte transendothelial migration, and some immune-related diseases. The levels of 23 immune cell types were higher in the C subtype than in the A and B subtypes. Finally, we developed and validated a riskscore based on TLS subtypes with better performance of prognosis prediction.

CONCLUSIONS

This study presents a new stratification method according to the TLS gene profile and highlights TLS heterogeneity in gliomas.

Proliferating CD8+ T Cell Infiltrates Are Associated with Improved Survival in Glioblastoma

Background: tumor-infiltrating lymphocytes are prognostic in many human cancers. However, the prognostic value of lymphocytes infiltrating glioblastoma (GBM), and roles in tumor control or progression are unclear. We hypothesized that B and T cell density, and markers of their activity, proliferation, differentiation, or function, would have favorable prognostic significance for patients with GBM. Methods: initial resection specimens from 77 patients with IDH1/2 wild type GBM who received standard-of-care treatment were evaluated with multiplex immunofluorescence histology (mIFH), for the distribution, density, differentiation, and proliferation of T cells and B cells, as well as for the presence of tertiary lymphoid structures (TLS), and IFNγ expression. Immune infiltrates were evaluated for associations with overall survival (OS) by univariate and multivariate Cox proportional hazards modeling. Results: in univariate analyses, improved OS was associated with high densities of proliferating (Ki67⁺) CD8⁺ cells (HR 0.36, p = 0.001) and CD20⁺ cells (HR 0.51, p = 0.008), as well as CD8⁺Tbet⁺ cells (HR 0.46, p = 0.004), and RORγt⁺ cells (HR 0.56, p = 0.04). Conversely, IFNγ intensity was associated with diminished OS (HR 0.59, p = 0.036). In multivariable analyses, adjusting for clinical variables, including age, resection extent, Karnofsky Performance Status (KPS), and MGMT methylation status, improved OS was associated with high densities of proliferating (Ki67⁺) CD8⁺ cells (HR 0.15, p < 0.001), and higher ratios of CD8⁺ cells to CD4⁺ cells (HR 0.31, p = 0.005). Diminished OS was associated with increases in patient age (HR 1.21, p = 0.005) and higher mean intensities of IFNγ (HR 2.13, p = 0.027). Conclusions: intratumoral densities of proliferating CD8 T cells and higher CD8/CD4 ratios are independent predictors of OS in patients with GBM. Paradoxically, higher mean intensities of IFNγ in the tumors were associated with shorter OS. These findings suggest that survival may be enhanced by increasing proliferation of tumor-reactive CD8⁺ T cells and that approaches may be needed to promote CD8⁺ T cell dominance in GBM, and to interfere with the immunoregulatory effects of IFNγ in the tumor microenvironment.