Tertiary lymphoid structures show infiltration of effective tumor-resident T cells in gastric cancer

Tissue-Resident Memory T Cells in Gastrointestinal Cancers: Prognostic Significance and Therapeutic Implications

Gastrointestinal cancers, which include a variety of esophageal and colorectal malignancies, present a global health challenge and require effective treatment strategies. In the evolving field of cancer immunotherapy, tissue-resident memory T cells (Trm cells) have emerged as important players in the immune response within nonlymphoid tissues. In this review, we summarize the characteristics and functions of Trm cells and discuss their profound implications for patient outcomes in gastrointestinal cancers. Positioned strategically in peripheral tissues, Trm cells have functions beyond immune surveillance, affecting tumor progression, prognosis, and response to immunotherapy. Studies indicate that Trm cells are prognostic markers and correlate positively with enhanced survival. Their presence in the tumor microenvironment has sparked interest in their therapeutic potential, particularly with respect to immune checkpoint inhibitors, which may improve cancer treatment. Understanding how Trm cells work will not only help to prevent cancer spread through effective treatment but will also contribute to disease prevention at early stages as well as vaccine development. The role of Trm cells goes beyond just cancer, and they have potential applications in infectious and autoimmune diseases. This review provides a thorough analysis of Trm cells in gastrointestinal cancers, which may lead to personalized and effective cancer therapies.

Analyzing the associations between tertiary lymphoid structures and postoperative prognosis, along with immunotherapy response in gastric cancer: findings from pooled cohort studies

BACKGROUND

The clinical significance of tertiary lymphoid structure (TLS) in gastric cancer (GC) was uncertain.

METHODS

A systematic search was performed in public databases for eligible studies as of April 2, 2023. Meta-analyses were performed to interrogate the associations between TLS levels and prognosis and immunotherapy response of GC. Bioinformatic analyses based on the nine-gene signature of TLS were further conducted to capture the biological underpinnings.

RESULTS

Eleven studies containing 4224 GC cases were enrolled in the meta-analysis. TLS levels positively correlated with smaller tumor size, earlier T stage and N stage. Moreover, higher TLS levels were detected in diffuse and mix subtypes of GC (P < 0.001). Higher TLS levels strongly predicted favorable postoperative overall survival of GC, with HR of 0.36 (95%CI 0.26-0.50, P < 0.001) and 0.55 (95%CI 0.45-0.68, P < 0.001) of univariate and multivariate Cox analysis, respectively. Higher TLS levels were also in favor of the treatment response of anti-PD-1 inhibitors as later-line therapy of GC. TLS levels positively correlated with immune effector cells infiltration, diversity and richness of T cell receptor and B cell receptor repertoire, immune checkpoint genes expression, and immune-related genes mutation of GC in the TCGA-STAD cohort, representing higher immunogenicity and immunoactivity. Moreover, moderate accuracy of TLS levels in predicting benefit from anti-PD-1 inhibitors in the PRJEB25780 cohort was also validated (AUC 0.758, 95%CI 0.583-0.933), higher than the microsatellite instability-score and Epstein-Barr virus status.

CONCLUSIONS

TLS levels demonstrated potential in predicting the postoperative prognosis and immunotherapy response of GC.

Mapping spatial heterogeneity in gastric cancer microenvironment

Gastric cancer (GC) is difficult to characterize due to its heterogeneity, and the complicated heterogeneity leads to the difficulty of precisely targeted therapy. The spatially heterogeneous composition plays a crucial role in GC onset, progression, treatment efficacy, and drug resistance. In recent years, the technological advancements in spatial omics has shifted our understanding of the tumor microenvironment (TME) from cancer-centered model to a dynamic and variant whole. In this review, we concentrated on the spatial heterogeneity within the primary lesions and between the primary and metastatic lesions of GC through the TME heterogeneity including the tertiary lymphoid structures (TLSs), the uniquely spatial organization. Meanwhile, the immune phenotype based on spatial distribution was also outlined. Furthermore, we recapitulated the clinical treatment in mediating spatial heterogeneity in GC, hoping to provide a systematic view of how spatial information could be integrated into anti-cancer immunity.

DeepRisk network: an AI-based tool for digital pathology signature and treatment responsiveness of gastric cancer using whole-slide images

BACKGROUND

Digital histopathology provides valuable information for clinical decision-making. We hypothesized that a deep risk network (DeepRisk) based on digital pathology signature (DPS) derived from whole-slide images could improve the prognostic value of the tumor, node, and metastasis (TNM) staging system and offer chemotherapeutic benefits for gastric cancer (GC).

METHODS

DeepRisk is a multi-scale, attention-based learning model developed on 1120 GCs in the Zhongshan dataset and validated with two external datasets. Then, we assessed its association with prognosis and treatment response. The multi-omics analysis and multiplex Immunohistochemistry were conducted to evaluate the potential pathogenesis and spatial immune contexture underlying DPS.

RESULTS

Multivariate analysis indicated that the DPS was an independent prognosticator with a better C-index (0.84 for overall survival and 0.71 for disease-free survival). Patients with low-DPS after neoadjuvant chemotherapy responded favorably to treatment. Spatial analysis indicated that exhausted immune clusters and increased infiltration of CD11b+CD11c+ immune cells were present at the invasive margin of high-DPS group. Multi-omics data from the Cancer Genome Atlas-Stomach adenocarcinoma (TCGA-STAD) hint at the relevance of DPS to myeloid derived suppressor cells infiltration and immune suppression.

CONCLUSION

DeepRisk network is a reliable tool that enhances prognostic value of TNM staging and aid in precise treatment, providing insights into the underlying pathogenic mechanisms.

Immune characteristics of dedifferentiated retroperitoneal liposarcomas and the reliability of regional samples in evaluating their tumor immune microenvironments

BACKGROUND

Tumor immunotherapy is a new treatment breakthrough for retroperitoneal liposarcoma (RPLS), which is highly invasive and has few effective treatment options other than tumor resection. However, the heterogeneity of the tumor immune microenvironment (TIME) leads to missed clinical diagnosis and inappropriate treatment. Therefore, it is crucial to evaluate whether the TIME of a certain part of the tumor reliably represents the whole tumor, particularly for very large tumors, such as RPLS.

METHODS

We conducted a prospective study to evaluate the TIME in different regions of dedifferentiated RPLS (DDRPLS) by detecting the expressions of markers such as CD4+, CD8+, Foxp3+, CD20+, CD68+, LAMP3+, PD-1+ tumor-infiltrating lymphocytes (TILs), and PD-L1 in tumors and corresponding paratumor tissues via immunohistochemistry and RNA sequencing.

RESULTS

In DDRPLS, very few TILs were observed. Differentially expressed genes were significantly enriched in cell part and cell functions, as well as the metabolic pathway and PI3K-Akt signaling pathway. In addition, for most tumors (70-80%), the TIME was similar in different tumor regions.

CONCLUSIONS

For most tumors (70-80%), the TIME in any region of the tumor reliably represents the whole tumor. DDRPLS may regulate cell functions by modulating the metabolic and PI3K-Akt signaling pathways to promote its malignant behavior.

ImmunoPET provides a novel way to visualize the CD103+ tissue-resident memory T cell to predict the response of immune checkpoint inhibitors

BACKGROUND

Immune checkpoint inhibitors (ICIs) have made significant progress in oncotherapy improving survival of patients. However, the benefits are limited to only a small subgroup of patients who could achieve durable responses. Early prediction of response may enable treatment optimization and patient stratification. Therefore, developing appropriate biomarkers is critical to monitoring efficacy and assessing patient response to ICIs.

MAIN BODY

Herein, we first introduce a new potential biomarker, CD103, expressed on tissue-resident memory T cells, and discuss the potential application of CD103 PET imaging in predicting immune checkpoint inhibitor treatment. In addition, we describe the current targets of ImmunoPET and compare these targets with CD103. To assess the benefit of PET imaging, a comparative analysis between ImmunoPET and other imaging techniques commonly employed for tumor diagnosis was performed. Additionally, we compare ImmunoPET and immunohistochemistry (IHC), a widely utilized clinical method for biomarker identification with respect to visualizing the immune targets.

CONCLUSION

CD103 ImmunoPET is a promising method for determining tumor-infiltrating lymphocytes (TILs) load and response to ICIs, thereby addressing the lack of reliable biomarkers in cancer immunotherapy. Compared to general T cell markers, CD103 is a specific marker for tissue-resident memory T cells, which number increases during successful ICI therapy. ImmunoPET offers noninvasive, dynamic imaging of specific markers, complemented by detailed molecular information from immunohistochemistry (IHC). Radiomics can extract quantitative features from traditional imaging methods, while near-infrared fluorescence (NIRF) imaging aids tumor detection during surgery. In the era of precision medicine, combining such methods will offer a more comprehensive approach to cancer diagnosis and treatment.

Multi-resolution deep learning characterizes tertiary lymphoid structures and their prognostic relevance in solid tumors

BACKGROUND

Tertiary lymphoid structures (TLSs) are dense accumulations of lymphocytes in inflamed peripheral tissues, including cancer, and are associated with improved survival and response to immunotherapy in various solid tumors. Histological TLS quantification has been proposed as a novel predictive and prognostic biomarker, but lack of standardized methods of TLS characterization hampers assessment of TLS densities across different patients, diseases, and clinical centers.

METHODS

We introduce an approach based on HookNet-TLS, a multi-resolution deep learning model, for automated and unbiased TLS quantification and identification of germinal centers in routine hematoxylin and eosin stained digital pathology slides. We developed HookNet-TLS using n = 1019 manually annotated TCGA slides from clear cell renal cell carcinoma, muscle-invasive bladder cancer, and lung squamous cell carcinoma.

RESULTS

Here we show that HookNet-TLS automates TLS quantification across multiple cancer types achieving human-level performance and demonstrates prognostic associations similar to visual assessment.

CONCLUSIONS

HookNet-TLS has the potential to be used as a tool for objective quantification of TLS in routine H&E digital pathology slides. We make HookNet-TLS publicly available to promote its use in research.

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.

Prognostic Impact of Tumor-Infiltrating Lymphocytes, Tertiary Lymphoid Structures, and Neutrophil-to-Lymphocyte Ratio in Pulmonary Metastases from Uterine Leiomyosarcoma

BACKGROUND

The presence of tumor-infiltrating lymphocytes (TILs) and tertiary lymphoid structures (TLSs) in tumor tissue has been related to the prognosis in various malignancies. Meanwhile, neutrophil-to-lymphocyte ratio (NLR) as a systemic inflammation marker also has been associated with the prognosis in them. However, few reports have investigated the relationship between pulmonary metastases from sarcoma and these biomarkers.

METHODS

We retrospectively recruited 102 patients undergoing metastasectomy for pulmonary metastases from uterine leiomyosarcoma at Okayama University Hospital from January 2006 to December 2019. TILs and TLSs were evaluated by immunohistochemical staining of surgically resected specimens of pulmonary metastases using anti-CD3/CD8/CD103/Foxp3/CD20 antibodies. NLR was calculated from the blood examination immediately before the most recent pulmonary metastasectomy. We elucidated the relationship between the prognosis and these factors. Because we considered that the status of tumor tissue and systemic inflammation were equally valuable, we also assessed the impact of the combination of TILs or TLSs and NLR on the prognosis.

RESULTS

As for TILs, CD3-positive cells and CD8-positive cells were correlated with the prognosis. The prognosis was significantly better in patients with CD3-high group, CD8-high group, TLSs-high group, and NLR-low group, respectively. The prognosis of CD8-high/NLR-low group and TLSs-high/NLR-low group was significantly better than that of CD8-low/NLR-high group and TLSs-low/NLR-high group, respectively.

CONCLUSIONS

CD3-positive TILs, CD8-positive TILs, TLSs, and NLR are correlated with the prognosis, respectively. The combination of CD8-positive TILs or TLSs and NLR may be the indicators to predict the prognosis of patients with pulmonary metastases from uterine leiomyosarcoma.

Development of [89Zr]Zr-hCD103.Fab01A and [68Ga]Ga-hCD103.Fab01A for PET imaging to noninvasively assess cancer reactive T cell infiltration: Fab-based CD103 immunoPET

BACKGROUND

CD103 is an integrin specifically expressed on the surface of cancer-reactive T cells. The number of CD103+ T cells significantly increases during successful immunotherapy and might therefore be an attractive biomarker for noninvasive PET imaging of immunotherapy response. Since the long half-life of antibodies preclude repeat imaging of CD103+ T cell dynamics early in therapy, we therefore here explored PET imaging with CD103 Fab fragments radiolabeled with a longer (89Zr) and shorter-lived radionuclide (68Ga).

METHODS

Antihuman CD103 Fab fragment Fab01A was radiolabeled with 89Zr or 68Ga, generating [89Zr]Zr-hCD103.Fab01A and [68Ga]Ga-hCD103.Fab01A, respectively. In vivo evaluation of these tracers was performed in male nude mice (BALB/cOlaHsd-Foxn1nu) with established CD103-expressing CHO (CHO.CD103) or CHO-wildtype (CHO.K1) xenografts, followed by serial PET imaging and ex vivo bio-distribution.

RESULTS

[89Zr]Zr-hCD103.Fab01A showed high tracer uptake in CD103+ xenografts as early as 3 h post-injection. However, the background signal remained high in the 3- and 6-h scans. The background was relatively low at 24 h after injection with sufficient tumor uptake. [68Ga]Ga-hCD103.Fab01Ashowed acceptable uptake and signal-to-noise ratio in CD103+ xenografts after 3 h, which decreased at subsequent time points.

CONCLUSION

[89Zr]Zr-hCD103.Fab01A demonstrated a relatively low background and high xenograft uptake in scans as early as 6 h post-injection and could be explored for repeat imaging during immunotherapy in clinical trials. 18F or 64Cu could be explored as alternative to 68Ga in optimizing half-life and radiation burden of the tracer.

Mechanisms and biomarkers of immune-related adverse events in gastric cancer

Immune-checkpoint inhibitors (ICIs), different from traditional cancer treatment models, have shown unprecedented anti-tumor effects in the past decade, greatly improving the prognosis of many malignant tumors in clinical practice. At present, the most widely used ICIs in clinical immunotherapy for a variety of solid tumors are monoclonal antibodies against cytotoxic T lymphocyte antigen-4 (CTLA-4), programmed cell death protein 1 (PD-1) and their ligand PD-L1. However, tumor patients may induce immune-related adverse events (irAEs) while performing immunotherapy, and irAE is an obstacle to the prospect of ICI treatment. IrAE is a non-specific disease caused by immune system imbalance, which can occur in many tissues and organs. For example, skin, gastrointestinal tract, endocrine system and lung. Although the exact mechanism is not completely clear, related studies have shown that irAE may develop through many ways. Such as excessive activation of autoreactive T cells, excessive release of inflammatory cytokines, elevated levels of autoantibodies, and common antigens between tumors and normal tissues. Considering that the occurrence of severe IrAE not only causes irreversible damage to the patient's body, but also terminates immunotherapy due to immune intolerance. Therefore, accurate identification and screening of sensitive markers of irAE are the main beneficiaries of ICI treatment. Additionally, irAEs usually require specific management, the most common of which are steroids and immunomodulatory therapies. This review aims to summarize the current biomarkers for predicting irAE in gastric cancer and their possible mechanisms.

Significance of CD103+ tissue-resident memory T cells for predicting the effectiveness of immune checkpoint inhibitors in esophageal cancer

BACKGROUND

Immune checkpoint inhibitors (ICIs), including nivolumab, have been approved to treat esophageal cancer. However, these remedies are not fit for all patients with esophageal cancer; therefore, a predictive surrogate marker is needed to assess their effectiveness. CD103+CD8+ tumor-infiltrating lymphocytes, defined as tissue-resident memory T cells (TRM), are promising indicators of response to ICIs, but it remains to be elucidated. This study investigated the association between the efficacy of ICIs and TRM.

METHODS

The relationships between TRM infiltrating esophageal cancer, clinicopathological features, and prognosis after nivolumab initiation were examined using immunostaining. Tissue samples were obtained from surgically resected specimens of 37 patients with esophageal cancer who received nivolumab as a secondary or subsequent therapy. In addition, TRM infiltration was compared with programmed death-ligand 1 (PD-L1) expression and blood count parameters as predictors of nivolumab effectiveness.

RESULTS

TRM-rich patients had a significant survival benefit after nivolumab initiation (12-months overall survival 70.8% vs 37.2%, p = 0.0485; 12-months progression-free survival 31.2% vs 0%, p = 0.0153) and experienced immune-related adverse events more frequently than TRM-poor patients (6 vs 2 patients). TRM infiltration was weakly correlated with PD-L1 positivity (r = 0.374, p = 0.022), but TRM may indicate more sensitive response to ICIs than PD-L1 expression in this study. Some blood test parameters also weakly correlated with TRM but did not impact prognosis.

CONCLUSIONS

TRM-rich patients have a favorable prognosis after nivolumab initiation. Our results suggest that TRM are vital for antitumor immunity and are a promising predictor of ICIs effectiveness.

The prognostic value of the tertiary lymphoid structure in gastrointestinal cancers

Background

Numerous studies and research papers have provided evidence suggesting that tertiary lymphoid structures (TLS) play a crucial role in combating and suppressing tumor growth and progression. Despite the wealth of information on the significance of TLS in various types of cancer, their prognostic value in gastrointestinal (GI) cancers remains uncertain. Therefore, this meta-analysis investigated the prognostic value of TLS in GI cancers.

Methods

We searched Web of science, Pubmed, Embase and Cochrane Library for studies that met the requirements as of May 1, 2023, and the hazard ratio (HR) and the corresponding 95% confidence interval (CI) were included in the analysis. The bioinformatics analysis results based on the TCGA database are used to supplement our research.

Results

The meta-analysis included 32 studies involving 5778 patients. The results of comprehensive analysis showed that TLS-High is associated with prolonged OS (HR=0.525,95%CI:0.447-0.616 (P < 0.001), RFS (HR=0.546,95%CI:0.461-0.647, P < 0.001), DFS (HR=0.519,95%CI:0.417-0.646, P < 0.001) and PFS (HR=0.588,95%CI:0.406-0.852, P=0.005) in GI cancer. Among the patients who received immunotherapy, TLS-High is associated with significantly prolonged OS (HR=0.475, 95%CI:0.282-0.799, P=0.005) and PFS(HR=0.576, 95%CI:0.381-0.871, P=0.009). It is worth noting that subgroup analysis showed that there was no significant relationship between TLS and OS(HR=0.775, 95%CI:0.570-1.053,P=0.103) in CRC. And when Present is used as the cut-off criteria of TLS, there is no significant correlation between TLS and OS (HR=0.850, 95%CI:0.721-1.002, P=0.053)in HCC.

Conclusion

TLS is a significant predictor of the prognosis of GI cancers and has the potential to become a prognostic biomarker of immunotherapy-related patients.

Systematic review registration

https://www.crd.york.ac.uk/PROSPERO/#recordDetails, identifier CRD42023443562.

The roles of tertiary lymphoid structures in chronic diseases

Tertiary lymphoid structures (TLSs) are ectopic lymphoid tissues that drive antigen-specific immune responses at sites of chronic inflammation. Unlike secondary lymphoid organs such as lymph nodes, TLSs lack capsules and have their own unique characteristics and functions. The presumed influence of TLSs on the disease course has led to widespread interest in obtaining a better understanding of their biology and function. Studies using single-cell analyses have suggested heterogeneity in TLS composition and phenotype, and consequently, functional correlates with disease progression are sometimes conflicting. The presence of TLSs correlates with a favourable disease course in cancer and infection. Conversely, in autoimmune diseases and chronic age-related inflammatory diseases including chronic kidney disease, the presence of TLSs is associated with a more severe disease course. However, the detailed mechanisms that underlie these clinical associations are not fully understood. To what extent the mechanisms of TLS development and maturation are shared across organs and diseases is also still obscure. Improved understanding of TLS development and function at the cellular and molecular levels may enable the exploitation of these structures to improve therapies for chronic diseases, including chronic kidney disease.

Prognostic relevance of tumor-resident memory T cells in metastatic lymph nodes of esophageal squamous cell carcinoma

Tumor-resident memory T (T_RM ) cells in primary tumors are reportedly associated with a favorable prognosis in several malignancies. However, the behaviors and functions of T_RM cells in regional lymph nodes (LNs) of esophageal cancer remain poorly understood. The aim of this study was to elucidate the effects of T_RM cells in regional LNs of esophageal cancer on clinicopathological findings and prognosis. Specimens of esophageal cancer and primary metastatic LNs (recurrent nerve LNs) were obtained from 84 patients who underwent radical esophagectomy between 2011 and 2017. We performed immunohistochemistry to enumerate and analyze T_RM cells, and used flow cytometry to investigate the function of T_RM cells. T_RM cells were observed in both metastatic LNs and primary tumors. T_RM cell-rich specimens exhibited reduced lymphatic invasion and LN metastasis and prolonged survival compared with T_RM cell-poor specimens. T_RM cells in metastatic LNs were more significantly associated with enhanced survival than T_RM cells in primary tumors. T_RM cells expressed high levels of granzyme B as a cytotoxicity marker. Our results suggested that high T_RM cell infiltration in metastatic LNs improves survival even though LN metastasis is commonly associated with poor prognosis. T_RM cells possibly contribute to antitumor immunity in regional LNs.

Tissue-resident memory T cells in gastrointestinal tumors: turning immune desert into immune oasis

Tissue-resident memory T cells (Trm) are a particular type of T cell subgroup, which stably reside in tissues and have been revealed to be the most abundant memory T cell population in various tissues. They can be activated in the local microenvironment by infection or tumor cells and rapidly clean them up to restore homeostasis of local immunity in gastrointestinal tissues. Emerging evidence has shown that tissue-resident memory T cells have great potential to be mucosal guardians against gastrointestinal tumors. Therefore, they are considered potential immune markers for immunotherapy of gastrointestinal tumors and potential extraction objects for cell therapy with essential prospects in clinical translational therapy. This paper systematically reviews the role of tissue-resident memory T cells in gastrointestinal tumors and looks to the future of their prospect in immunotherapy to provide a reference for clinical application.

The Role of Interleukin-7 in the Formation of Tertiary Lymphoid Structures and Their Prognostic Value in Gastrointestinal Cancers

Immunotherapies for the treatment of solid tumors continue to develop in preclinical and clinical research settings. Unfortunately, for many patients the tumor fails to respond or becomes resistant to therapies such as checkpoint inhibitors (CPIs) targeting programmed cell death protein-1 (PD-1), programmed death-ligand 1 (PD-L1), and cytotoxic T lymphocyte antigen-4 (CTLA-4). In many cancers, failed response to CPIs can be attributed to poor T cell infiltration, dominant immunosuppression, and exhausted immune responses. In gastrointestinal (GI) cancers T cell infiltration can be dismal, with several reports finding that CD8⁺ T cells compose less than 2% of all cells within the tumor. Organized aggregates of lymphocytes, antigen-presenting cells, and vessels, together termed tertiary lymphoid structures (TLSs), are hypothesized to be a major source of T cells within solid tumors. The intratumoral formation of these organized immune centers appears to rely on intricate cytokine and chemokine signaling to heterogeneous cell populations such as B and T cells, innate lymphoid cells, fibroblasts, and dendritic cells. In GI cancers, the presence and density of TLSs provide prognostic value for predicting outcome and survival. Further, TLS presence and density associates with favorable responses to CPIs in many cancers. This review highlights the prognostic value of TLSs in GI cancers, the role of the homeostatic cytokine interleukin-7 (IL-7) in TLS formation, and the induction of TLSs in solid tumors by novel therapeutics.

Tertiary lymphoid structures: Associated multiple immune cells and analysis their formation in hepatocellular carcinoma

The prognostic value of immune cells in tertiary lymphoid structures (TLSs) remains unclear in hepatocellular carcinoma (HCC). Here, 59 of 145 patients had TLSs in training set, 48 of 120 patients had TLSs in testing set. Immunohistochemistry (IHC) were used to label CD3+ T cells, CD20+ B cells, CD8+ T cells, CD208+ dendritic cells, and CD21+ follicular dendritic cells in TLSs. High CD20+, CD208+, and CD8+ cell densities were favorable prognostic factors for overall survival (OS). High CD3+, CD20+, CD208+, and CD8+ cell densities were significantly associated with reduced early recurrence. TLSs were divided into three grades (A, B, and C) based on immune cell density. Patients with grade C or B had significantly improved OS. Patients with grade C had the lowest recurrence rate, followed by those with grade B, while patients with grade A had the highest recurrence rate. The stromal, immune, and ESTIMATE scores derived from the ESTIMATE package were significantly higher and tumor purity was significantly lower in patients with TLSs. Patients with TLSs had significantly higher relative numbers of memory B cells, plasma cells, CD8+ T cells, NK cells, and dendritic cells and lower relative numbers of Treg cells, macrophages, and M2 macrophages according to the CIBERSORT assessment. Bioinformatics analysis and experiments confirmed that KLRK1 and GZMA expression are associated TLSs formation and can predict TLSs existence. Grade B and grade C were favorable prognostic factors for OS and recurrence and could represent immune-active tumors.

NKG2A and HLA-E define an alternative immune checkpoint axis in bladder cancer

Programmed cell death protein 1 (PD-1)/programmed death-ligand 1 (PD-L1)-blockade immunotherapies have limited efficacy in the treatment of bladder cancer. Here, we show that NKG2A associates with improved survival and responsiveness to PD-L1 blockade immunotherapy in bladder tumors that have high abundance of CD8+ T cells. In bladder tumors, NKG2A is acquired on CD8+ T cells later than PD-1 as well as other well-established immune checkpoints. NKG2A+ PD-1+ CD8+ T cells diverge from classically defined exhausted T cells through their ability to react to human leukocyte antigen (HLA) class I-deficient tumors using T cell receptor (TCR)-independent innate-like mechanisms. HLA-ABC expression by bladder tumors is progressively diminished as disease progresses, framing the importance of targeting TCR-independent anti-tumor functions. Notably, NKG2A+ CD8+ T cells are inhibited when HLA-E is expressed by tumors and partly restored upon NKG2A blockade in an HLA-E-dependent manner. Overall, our study provides a framework for subsequent clinical trials combining NKG2A blockade with other T cell-targeted immunotherapies, where tumors express higher levels of HLA-E.

Emerging concepts regarding pro- and anti tumor properties of B cells in tumor immunity

Controversial views regarding the roles of B cells in tumor immunity have existed for several decades. However, more recent studies have focused on its positive properties in antitumor immunity. Many studies have demonstrated a close association of the higher density of intratumoral B cells with favorable outcomes in cancer patients. B cells can interact with T cells as well as follicular dendritic cells within tertiary lymphoid structures, where they undergo a series of biological events, including clonal expansion, somatic hypermutation, class switching, and tumor-specific antibody production, which may trigger antitumor humoral responses. After activation, B cells can function as effector cells via direct tumor-killing, antigen-presenting activity, and production of tumor-specific antibodies. At the other extreme, B cells can obtain inhibitory functions by relevant stimuli, converting to regulatory B cells, which serve as an immunosuppressive arm to tumor immunity. Here we summarize our current understanding of the bipolar properties of B cells within the tumor immune microenvironment and propose potential B cell-based immunotherapeutic strategies, which may help promote cancer immunotherapy.

Clinical relevance of tertiary lymphoid structures in esophageal squamous cell carcinoma

BACKGROUND

Tertiary lymphoid structures (TLSs) have been reported to be involved in immune responses in many carcinomas. This study investigated the significance of TLSs in esophageal squamous cell carcinoma, focusing on TLS maturation.  METHODS: The relationships of TLSs with clinicopathological features of 236 patients who underwent curative surgery for stage 0-IV esophageal squamous cell carcinoma were investigated. Mature TLSs, in which the germinal center formation was rich in CD23⁺ cells, were classified as TLSs containing a germinal center (GC-TLSs). GC-TLS densities were measured, and CD8⁺ cells were counted. The prognostic impact of GC-TLSs was assessed by Kaplan-Meier plots using the log-rank test for the relapse-free survival. A comparative study of GC-TLSs was performed using the Wilcoxon rank sum test. The relationship between GC-TLSs and CD8⁺ cells was examined by Spearman's rank correlation coefficient test.

RESULTS

TLSs were located mainly at the invasive margin of the tumor in cases with esophageal squamous cell carcinoma. Among the patients treated with neoadjuvant chemotherapy, those with advanced disease had a better prognosis in the GC-TLS high-density group than did those in the GC-TLS low-density group. Patients in whom neoadjuvant chemotherapy was effective had more GC-TLSs than those in whom it was less effective. The density of GC-TLSs and the number of tumor-infiltrating CD8⁺ cells were higher in patients treated with neoadjuvant chemotherapy than in those without chemotherapy, and a weak correlation between the density of GC-TLSs and the number of tumor-infiltrating CD8⁺ cells was observed. Moreover, co-culturing of PBMCs with an anticancer drug-treated esophageal squamous cell carcinoma cell line increased the CD20 and CD23 expression in PBMCs in vitro.

CONCLUSION

TLS maturation may be important for evaluating the local tumor immune response in patients treated with neoadjuvant chemotherapy for esophageal squamous cell carcinoma. The present results suggest that TLS maturation may be a useful target for predicting the efficacy of immunotherapy, including immune checkpoint inhibitor treatment for esophageal squamous cell carcinoma.

Tumor-Resident T Cells, Associated With Tertiary Lymphoid Structure Maturity, Improve Survival in Patients With Stage III Lung Adenocarcinoma

Tertiary lymphoid structure (TLS) and tumor-resident memory T cells (TRM) play crucial roles in the anti-tumor immune response, facilitating a good prognosis in patients with cancer. However, there have been no reports on the relationship between TRM and TLS maturity. In this study, we detected TRM and the maturity of TLS by immunofluorescence staining and analyzed the relationship between their distribution and proportion in patients with lung adenocarcinoma (LUAD). The proportion of TRM within TLSs was significantly higher than that outside and was positively correlated with the survival of patients. In addition, the proportions of CD4+CD103+ TRM and CD8+CD103+ TRM were significantly increased with the gradually maturation of TLSs. We divided the patients into three levels (grade 1, grade 2, and grade 3) according to the presence of increasing maturation of TLSs. The proportion of CD103+ TRM in grade 3 patients was significantly higher than that in grade 1 and grade 2 patients, suggesting a close relationship between CD103+ TRM and TLS maturity. Furthermore, positive prognosis was associated with grade 3 patients that exhibited CD103+T RM High phenotype.

CD103+ T Cells May Be a Useful Biomarker in Borrmann Type 4 Gastric Cancer

BACKGROUND/AIM

Recently, several studies have reported that CD103 ⁺  T cells are associated with antitumor immunity in gastric cancer (GC). However, the significance of CD103 ⁺  T cells in Borrmann type 4 GC remains unclear. The aim of this study is to assess the association of CD103 ⁺ T cells with type 4 GC.

MATERIALS AND METHODS

Tissue samples obtained from surgically resected specimens of patients with type 4 GC were collected, and immunohistochemical staining was performed to detect the presence of CD103 ⁺ T cells.

RESULTS

A total of 46 patients were analyzed. In some patients, high CD103 expression was observed, and patients with high CD103 expression tended to have a better prognosis than those with low CD103 expression. In particular, for patients who receive doublet chemotherapy after surgery, high CD103 expression was associated with a good prognosis.

CONCLUSION

CD103 ⁺ T cells may be a prognostic marker in type 4 GC.

The Emerging Role of Tissue-Resident Memory CD8+ T Lymphocytes in Human Digestive Tract Cancers

Malignant digestive tract tumors are a great threat to human public health. In addition to surgery, immunotherapy brings hope for the treatment of these tumors. Tissue-resident memory CD8⁺ T (Trm) cells are a focus of tumor immunology research and treatment due to their powerful cytotoxic effects, ability to directly kill epithelial-derived tumor cells, and overall impact on maintaining mucosal homeostasis and antitumor function in the digestive tract. They are a group of noncirculating immune cells expressing adhesion and migration molecules such as CD69, CD103, and CD49a that primarily reside on the barrier epithelium of nonlymphoid organs and respond rapidly to both viral and bacterial infection and tumorigenesis. This review highlights new research exploring the role of CD8⁺ Trm cells in a variety of digestive tract malignant tumors, including esophageal cancer, gastric cancer, colorectal cancer, and hepatocellular carcinoma. A summary of CD8⁺ Trm cell phenotypes and characteristics, tissue distribution, and antitumor functions in different tumor environments is provided, illustrating how these cells may be used in immunotherapies against digestive tract tumors.

Clinical efficacy of nivolumab is associated with tertiary lymphoid structures in surgically resected primary tumors of recurrent gastric cancer

Nivolumab, an immune checkpoint blocker, has been approved for advanced gastric cancer (GC), but predictive factors of nivolumab’s efficacy in patients with GC, especially immune cells such as tissue-resident memory T cells or those forming tertiary lymphoid structures (TLS), remain unclear. Tissue samples were obtained from surgically resected specimens of patients with GC who were treated with nivolumab as third-line or later treatment. Immunohistochemical staining was performed to detect the presence of TLS and CD103+ T cells and assess the association between TLSs and response to nivolumab treatment. A total of 19 patients were analyzed. In patients with partial response (PR) to nivolumab, numerous TLS were observed, and CD103+ T cells were found in and around TLS. Patients with many TLS experienced immune-related adverse events more often than those with few TLS (p = 0.018). The prognosis of patients with TLS high was better than those with TLS low. Patients with a combination of TLS high and CD103 high tended to have a better prognosis than other groups. Our results suggested that TLS status might be a predictor of nivolumab effectiveness.

Human mucosal tissue-resident memory T cells in health and disease

Memory T cells are fundamental to maintain immune surveillance of the human body. During the past decade, it has become apparent that non-recirculating resident memory T cells (TRMs) form a first line memory response in tissues to tackle re-infections. The fact that TRMs are essential for local immunity highlights the therapeutic potential of targeting this population against tumors and infections. However, similar to other immune subsets, TRMs are heterogenous and may form distinct effector populations with unique functions at diverse tissue sites. Further insight into the mechanisms of how TRM function and respond to pathogens and malignancies at different mucosal sites will help to shape future vaccine and immunotherapeutic approaches. Here, we review the current understanding of TRM function and biology at four major mucosal sites: gastrointestinal tract, lung, head and neck, as well as female reproductive tract. We also summarize our current knowledge of how TRM targets invading pathogens and developing tumor cells at these mucosal sites and contemplate how TRMs may be exploited to protect from infections and cancer.

Conversion therapy with tislelizumab for high microsatellite instability, unresectable stage III gastric cancer: a case report

Gastric cancer (GC) is the fifth-highest ranked cancer for incidence and second for mortality from cancer worldwide. Conversion therapy has recently emerged as an alternative therapy for advanced/metastatic GC patients who are unable to undergo surgical resection at the time of diagnosis. Herein, we present the case of a patient with unresectable stage III GC of high microsatellite instability (MSI), high tumor mutation burden (TMB), and Epstein-Barr virus (EBV) positive. The patient received conversion therapy involving a combination of chemotherapy and immunotherapy regimens. After 3 courses of chemotherapy combined with tislelizumab, the patient underwent laparoscopic radical total gastrectomy. The pathological examination demonstrated that there was no cancerous tissue at the proximal or distal end of the tumor and no lymph node metastases in the lesser or greater curvature, indicating a pathologic complete response. Thereafter, the patient continued tislelizumab treatment to prevent postoperative carcinoma recurrence and metastasis, and to improve prognosis. In conclusion, our study confirmed that chemotherapy combined with immunotherapy is a promising conversion therapy for GC patients with locally unresectable lesions or distant lymph node metastasis, and these findings warrant large-scale clinical studies. This report highlights the clinical importance of next-generation sequencing technology in investigating therapeutic strategy to provide the maximal clinical benefit for patients with GC.

Tertiary lymphoid structures show infiltration of effective tumor-resident T cells in gastric cancer

Several studies have reported that tissue‐resident memory T cells (TRM cells) or tertiary lymphoid structures (TLSs) are associated with a good prognosis. The aim of this study was to clarify the association of TRM cells and TLSs in the tumor immune microenvironment in gastric cancer (GC). We performed immunohistochemical and immunofluorescence staining to detect the presence of CD103⁺ T cells and to assess the association between CD103⁺ T cells and TLSs. CD103⁺ T cells were observed in the tumor epithelium accompanied by CD8⁺ T cells and were associated with a better prognosis in GC. Furthermore, CD103⁺ T cells were located around TLSs, and patients with CD103^high had more rich TLSs. Patients who had both CD103^high cells and who were TLS‐rich had a better prognosis than patients with CD103^low cells and who were TLS‐poor. Moreover, for patients who received PD‐1 blockade therapy, CD103^high and TLS‐rich predicted a good response. Flow cytometry was performed to confirm the characteristics of CD103⁺CD8⁺ T cells and showed that CD103⁺CD8⁺ T cells in GC expressed higher levels of PD‐1, granzyme B, and interferon‐γ than CD103⁻CD8⁺ T cells. Our results suggested that CD103⁺CD8⁺ cells in GC are correlated with TLSs, resulting in enhanced antitumor immunity in GC.