Predictive value of tumor-infiltrating lymphocytes for neoadjuvant therapy response in triple-negative breast cancer: A systematic review and meta-analysis

BACKGROUND The association between tumor-infiltrating lymphocyte(TIL)levels and the res-ponse to neoadjuvant therapy(NAT)in patients with triple-negative breast cancer(TNBC)remains unclear.AIM To investigate the predictive potential of TIL levels for the response to NAT in TNBC patients.METHODS A systematic search of the National Center for Biotechnology Information PubMed database was performed to collect relevant published literature prior to August 31,2023.The correlation between TIL levels and the NAT pathologic com-plete response(pCR)in TNBC patients was assessed using a systematic review and meta-analysis.Subgroup analysis,sensitivity analysis,and publication bias analysis were also conducted.RESULTS A total of 32 studies were included in this meta-analysis.The overall meta-ana-lysis results indicated that the pCR rate after NAT treatment in TNBC patients in the high TIL subgroup was significantly greater than that in patients in the low TIL subgroup(48.0%vs 27.7%)(risk ratio 2.01;95%confidence interval 1.77-2.29;P<0.001,I2=56%).Subgroup analysis revealed that the between-study hetero-geneity originated from differences in study design,TIL level cutoffs,and study populations.Publication bias could have existed in the included studies.The meta-analysis based on different NAT protocols revealed that all TNBC patients with high levels of TILs had a greater rate of pCR after NAT treatment in all protocols(all P≤0.01),and there was no significant between-protocol difference in the statistics among the different NAT protocols(P=0.29).Additionally,sensitivity analysis demonstrated that the overall results of the meta-analysis remained consistent when the included studies were individually excluded.CONCLUSION TILs can serve as a predictor of the response to NAT treatment in TNBC patients.TNBC patients with high levels of TILs exhibit a greater NAT pCR rate than those with low levels of TILs,and this predictive capability is con-sistent across different NAT regimens.

Tumor-infiltrating T-Lymphocyte immunity-related immune tolerance and anti–programmed cell death protein 1/ligand of programmed cell death protein 1 therapy for advanced hepatocellular carcinoma

Systemic therapy has become the standard treatment for patients with advanced hepatocellular carcinoma(HCC)whose treatment options are limited.However,the long-term patient response to drugs and the survival outcomes remain a concern.With increasing exploration of the HCC microenvironment,particularly in terms of T lymphocyte immunity,a new era of immunomolecular targeted therapy,based on molecular signaling,has arrived for advanced HCC.In the study of immune tolerance of the intrinsic HCC microenvironment,we found that multiple immunosuppressive mechanisms and immune checkpoint inhibitors,such as anti–programmed cell death protein 1/ligand of programmed cell death protein 1 therapy,have improved clinical outcomes in some patients with advanced HCC.Furthermore,various combination therapies have been investigated,and HCC types have been categorized into different types based on anti–programmed cell death protein 1(PD-1)/ligand of programmed cell death protein 1(PD-L1)treatment.In this paper,we first discuss the tumor-infiltrating T lymphocyte immunity and immune tolerance of HCC.We then clarify the basic mechanism of anti–PD-1/PD-L1 therapy and discuss the types of HCC based on anti–PD-1/PD-L1 therapy.Thereafter,we explain the relevant studies and mechanisms of combination therapy of anti–PD-1/PD-L1 with antiangiogenesis drugs or multikinase kinase inhibitors,anti–T lymphocyte–related signaling pathways in HCC,and other anti-CD8+T cell immune checkpoints.In this way,this review offers a deeper understanding of anti–PD-1/PD-L1 immunotherapy for advanced HCC,in order to provide better individualized treatments for patients with advanced HCC.

LAG-3 expression on tumor-infiltrating T cells in soft tissue sarcoma correlates with poor survival

Objective: To elucidate the role and prognostic significance of lymphocyte activation-gene-3(LAG-3) in soft tissue sarcoma(STS).Methods: The expression of LAG-3 in patient and matched normal blood samples was analyzed by flow cytometry. The localization and prognostic values of LAG-3^+ cells in 163 STS patients were analyzed by immunohistochemistry. In addition, the expression of tumor-infiltrating CD3^+ T, CD4^+ T, and CD8^+ T cells and their role in the prognosis of STS were evaluated by immunohistochemistry. The effect of LAG-3 blockade was evaluated in an immunocompetent MCA205 fibrosarcoma mouse model.Results: Peripheral CD8^+ and CD4^+ T cells from STS patients expressed higher levels of LAG-3 than those from healthy donors.LAG-3 expression in STS was significantly associated with a poor clinical outcome(P = 0.038) and was correlated with high pathological grade(P < 0.001), advanced tumor stage(P = 0.016). Additionally, LAG-3 expression was highly correlated with CD8^+ T-cell infiltration(r = 0.7034, P < 0.001). LAG-3 was expressed in murine tumor-infiltrating lymphocytes, and its blockade decreased tumor growth and enhanced secretion of interferon-gamma by CD8^+ and CD4^+ T cells.Conclusions: LAG-3 blockade may be a promising strategy to improve the effects of targeted therapy in STS.

Clinical significance of tumor-infiltrating lymphocytes for gastric cancer in the era of immunology

Immunotherapy has begun to revolutionize cancer treatment, by introducing therapies that target the host immune system instead of the tumor, therapies that possess unique adverse event profiles, and therapies that may cure certain types of cancer. The immune microenvironment of tumors is emerging as the most important means of understanding the relationship between a patient' immune system and their cancer, informing prognosis, and guiding immunotherapy, such as an antibody blockade of immune checkpoints. For some solid tumors, simple quantitation of lymphocyte infiltration would seem to have prognostic significance, suggesting that lymphocyte infiltration is not passive but may actively promote or inhibit tumor growth. For gastric cancers, several studies have provided strong evidence that immune cells contribute to determining prognosis. However, the exact role of immune cells in gastric cancer remains unclear. Therefore, this review focuses on the clinical significance of immune cells, especially tumor-infiltrating lymphocytes, in gastric cancer.

Association between Up-regulation of Fas Ligand Expression and Apoptosis of Tumor-infiltrating Lymphocytes in Human Breast Cancer

In order to study the significance of FasL expression in immune escape of breast cancer, FasL protein expression and the number of tumor-infiltrating lymphocytes （TILs） in 40 specimens of breast cancer were detected by immunohistochemitry. The expression of FasL mRNA was measured by in situ hybridization in the consecutive tissue slices of 40 breast cancers respectively. By using terminal deoxynucleotidyl transferase-mediaed dUTP nick end labeling （TUNEL）, apoptotic cells were detected in 40 specimens of breast cancer. The expression of FasL was detected in all 40 specimens to varying degrees. In the consecutive tissue slices, the location of expression of FasL protein corresponded with that of FasL mRNA. In those with FasL extensive expression, the number of TILs was less （P〈0.05）, the apoptotic index （AI） of TILs was higher and the AI of tumor cells was lower （P〈0.01） than those with FasL weak expression respectively. The AI of TILs was correlated with that of tumor cells （r=-0.629, P〈0.01）. In conclusion, breast cancer cells can induce the apoptosis of TILs through the expression of FasL, which can counterattack the immune system. This may be a mechanism of immune evasion in breast cancer.

Tumor-infiltrating platelets predict postoperative recurrence and survival in resectable pancreatic neuroendocrine tumor

BACKGROUND Platelets have been reported to participate in tumor cell growth,extravasation,epithelial–mesenchymal transition,metastasis,and drug resistance.However,the importance of platelets in pancreatic neuroendocrine tumor(pNET)lacks adequate literature support.The predictive value of tumor-infiltrating platelets(TIPs)in pNET remains unclear.AIM To investigate the relationship between TIPs and the prognosis of patients with pNET following radical resection.METHODS In total,113 patients who had undergone radical surgical resection with a pathologic diagnosis of pNET were enrolled in this study.Immunohistochemical analysis of cluster of differentiation 42b(CD42b)expression in the tumor specimens was performed to determine the presence of TIPs.Univariate and multivariate analyses were used to analyze the prognostic value of TIPs.RESULTS TIPs were observed in intratumoral areas in 54 patients.Neither basic characteristics nor preoperative platelet-associated indicators showed a significant relationship with the presence of TIPs(all P>0.05).Patients with positive intratumoral CD42b expression had worse overall survival(P=0.005)and recurrence-free survival(P<0.001)than those with negative intratumoral CD42b expression.Multivariate analysis demonstrated that TIPs were independent prognostic factors for overall survival(P=0.049)and recurrencefree survival(P=0.003).Nevertheless,platelet count,mean platelet volume,and platelet-to-lymphocyte ratio were not associated with postoperative survival or recurrence in pNET patients(all P>0.05).CONCLUSION TIPs are a useful prognostic biomarker for patients with resectable pNET,and their detection represents a promising tool for pNET treatment strategy decisions.

Heterogeneity of tumor-infiltrating myeloid cells in era of single-cell genomics

Tumor microenvironment(TME)is highly heterogeneous and composed of complex cellular components,including multiple kinds of immune cells.Among all immune cells in TME,tumor-infiltrating myeloid cells(TIMs)account for a large proportion and play roles as key regulators in a variety of functions,ranging from immune-mediated tumor killing to tumor immune evasion.Understanding the heterogeneity of TIMs will provide valuable insights for new therapeutic targeting of myeloid cells.Single-cell genomic technologies deciphering cell composition and gene expression at single-cell resolution have largely improved our understanding of the cellular heterogeneity of TIMs and highlighted several novel cell subtypes contributing to the variation of patient survival and treatment response.However,these cell subtypes were defined based on limited data without a concordant nomenclature,which makes it difficult to understand whether they exist in different studies.Thus,in this review,we comprehensively summarized the common agreements and current different opinions on the heterogeneity of TIMs gained from single-cell studies;evaluated the feasibility of current myeloid cell targets at single-cell level and proposed a uniform nomenclature for TIM subsets.

Prognostic implications of tumor-infiltrating lymphocytes in association with programmed cell death ligand 1 expression in remnant gastric cancer

Objective:Remnant gastric cancer(RGC)is usually associated with a worse prognosis.As they are less common and very heterogeneous tumors,new prognostic and reliable determinants are required to predict patients’clinical course for RGC.This study aimed to investigate the tumor-infiltrating lymphocytes(TILs)and programmed cell death ligand 1(PD-L1)status as prognostic biomarkers in a cohort of patients with RGC to develop an immunerelated score.Methods:Patients with gastric cancer(GC)who underwent curative intent gastrectomy were retrospectively investigated.RGC resections with histological diagnosis of gastric adenocarcinoma were enrolled in the study.The risk score based on immune parameters was developed using binary logistic regression analysis.RGCs were divided into high-risk(HR),intermediate-risk(IR),and low-risk(LR)groups based on their immune score.The markers(CD3+,CD4+/CD8+T cells and PD-L1)were selected for their potential prognostic,therapeutic value,and evaluated by immunohistochemistry(IHC).Results:A total of 42 patients with RGC were enrolled in the study.The score based on immune parameters exhibited an accuracy of 79%[the area under the receiver operating characteristic curve(AUC)=0.79,95%confidence interval(95%CI),0.63-0.94,P=0.002],and the population was divided into 3 prognostic groups:10(23.8%)patients were classified as LR,15(35.7%)as IR,and 17(40.5%)as HR groups.There were no differences in clinicopathological and surgical characteristics between the three groups.In survival analysis,HR and IR groups had worse disease-free survival and overall survival rates compared to the LR group.In the multivariate analysis,lymph node metastasis and the immune score risk groups were independent factors related to worse survival.Conclusions:A scoring system with immune-related markers was able to distinguish prognostic groups of RGC associated with survival.Accordingly,tumor-infiltrating immune lymphocytes and PD-L1 status may serve as a potential prognostic biomarker for patients with RGC.

Change of tumor-infiltrating lymphocyte of associating liver partition and portal vein ligation for staged hepatectomy for hepatocellular carcinoma

BACKGROUND The role of tumor-infiltrating lymphocytes(TILs)in the growth and progression of hepatocellular carcinoma(HCC)has attracted widespread attention.AIM To evaluate the feasibility of associating liver partition and portal vein ligation for staged hepatectomy(ALPPS)for massive HCC by exploring the role of TIL in the tumor microenvironment.METHODS Fifteen massive HCC patients who underwent ALPPS treatment and 46 who underwent hemi-hepatectomy were selected for this study.Propensity score matching was utilized to match patients in ALPPS and hemi-hepatectomy groups(1:1).Quantitative analysis of TILs in tumor and adjacent tissues between the two groups was performed by immunofluorescence staining and further analyses with oncological characteristics.In the meantime,trends of TILs in peripheral blood RESULTS Continuous measurement of tumor volume and necrosis volume showed that the proportion of tumor necrosis volume on the seventh day after stage-I ALPPS was significantly higher than the pre-operative value(P=0.024).In the preoperative period of stage-I ALPPS,the proportion of tumor necrosis volume in the high CD8+T cell infiltration group was significantly higher than that in the low group(P=0.048).CONCLUSION TIL infiltration level maintained a dynamic balance during the preoperative period of ALPPS.Compared with right hemi-hepatectomy,the ALPPS procedure does not cause severe immunosuppression with the decrease in TIL infiltration and pathological changes in immune components of peripheral blood.Our results suggested that ALPPS is safe and feasible for treating massive HCC from the perspective of immunology.In addition,high CD8+T cell infiltration is associated with increasing tumor necrosis in the perioperative period of ALPPS.

Tumor-infiltrating B cells come into vogue

Lymphocyte infiltration into solid tumors has been recognized as a main determinator of positive prognosis.For the most part this is attributed to cytotoxic T cells capable of directly destroying malignant cells.However,when considering the complex composition of the human immune system,recent findings of Nielsenet al on a potentially central role of tumor-infiltrating B cells is not really surprising.In this commentary article,I want to highlight the enormous potential impact of this observation for basic and translational research,prognostic procedures and ultimately for the development of future therapeutic concepts.

IN VITRO ANTITUMOR ACTIVITY OF TUMOR-INFILTRATING LYMPHOCYTES FROM HUMAN GASTRIC CARCINOMA

Tumor-infiltrating lymphocytes (TIL) isolated from 11 gastric carcinoma were studied. TIL could grow for a long-term in medium containing recombi-nant interleukin-2(rlL-2). The mean expansion fold achieved in 6 long-term cultures of 11 specimens was 15.1. RIL-2 expanded gastric TIL exhibited significant cytotoxicity against K562, BGC823, MCF-7 and more effective antitumor cytotoxicity against fresh autologous tumor targets and human gastric cancer cell line. Peak cytotoxicity was shown in the third or fourth week after cultures. Cryopreservation of gastric TIL didn't influence their expansion capacity and antitumor activity. Phenotypic analysis was demonstrated in this study. The results of present study indicate that TIL from human gastric carcinoma could be expanded and reach high levels of antitumor effector function in long-term cultures with rIL-2. Their function may be of clinical importance.

The history and advances in cancer immunotherapy:understanding the characteristics of tumor-infiltrating immune cells and their therapeutic implications

Immunotherapy has revolutionized cancer treatment and rejuvenated the field of tumor immunology.Several types of immunotherapy,including adoptive cell transfer(ACT)and immune checkpoint inhibitors(ICIs),have obtained durable clinical responses,but their efficacies vary,and only subsets of cancer patients can benefit from them.Immune infiltrates in the tumor microenvironment(TME)have been shown to play a key role in tumor development and will affect the clinical outcomes of cancer patients.Comprehensive profiling of tumor-infiltrating immune cells would shed light on the mechanisms of cancer–immune evasion,thus providing opportunities for the development of novel therapeutic strategies.However,the highly heterogeneous and dynamic nature of the TME impedes the precise dissection of intratumoral immune cells.With recent advances in single-cell technologies such as single-cell RNA sequencing(scRNA-seq)and mass cytometry,systematic interrogation of the TME is feasible and will provide insights into the functional diversities of tumor-infiltrating immune cells.In this review,we outline the recent progress in cancer immunotherapy,particularly by focusing on landmark studies and the recent single-cell characterization of tumor-associated immune cells,and we summarize the phenotypic diversities of intratumoral immune cells and their connections with cancer immunotherapy.We believe such a review could strengthen our understanding of the progress in cancer immunotherapy,facilitate the elucidation of immune cell modulation in tumor progression,and thus guide the development of novel immunotherapies for cancer treatment.

Tumor-infiltrating B cells:their role and application in antitumor immunity in lung cancer

Evidence indicates that lung cancer development is a complex process that involves interactions between tumor cells,stromal fibroblasts,and immune cells.Tumor-infiltrating immune cells play a significant role in the promotion or inhibition of tumor growth.As an integral component of the tumor microenvironment,tumor-infiltrating B lymphocytes(TIBs)exist in all stages of cancer and play important roles in shaping tumor development.Here,we review recent clinical and preclinical studies that outline the role of TIBs in lung cancer development,assess their prognostic significance,and explore the potential benefit of B cell-based immunotherapy for lung cancer treatment.

Programmed death-1 upregulation is correlated with dysfunction of tumor-infiltrating CD8^(+ ) T lymphocytes in human non-small cell lung cancer

T-cell tolerance is an important mechanism for tumor escape,but the molecular pathways involved in T-cell tolerance remain poorly understood.It remains unknown whether the inhibitory immunoreceptor programmed death-1(PD-1)plays a role in conditions of human non-small cell lung cancer(NSCLC).In this study,we detected PD-1 expression on CD81 T cells from healthy control peripheral blood mononuclear cells(PBMCs)and the PBMCs of NSCLC patients as well as NSCLC tissues.Results showed that tumor-infiltrating CD81 T cells had increased PD-1 expression and impaired immune function,including reducing cytokine production capability and impairing capacity to proliferate.Blockade of the PD-1/PD-L1 pathway by the PD-L1-specific antibody partially restored cytokine production and cell proliferation.These data provide direct evidence that the PD-1/PD-L1 pathway is involved in CD81 T-cell dysfunction in NSCLC patients.Moreover,blocking this pathway provides a potential therapy target in lung cancer.

A reversed CD4/CD8 ratio of tumor-infiltrating lymphocytes and a high percentage of CD4^(+)FOXP3^(+) regulatory T cells are significantly associated with clinical outcome in squamous cell carcinoma of the cervix

In this study,40 biopsy samples collected from cervical cancer patients at the First Affiliated Hospital of Xi’an Jiaotong University,China,were retrospectively assessed using immunohistochemistry for CD4^(+) and CD8^(+) tumor-infiltrating lymphocytes(TILs)and were analyzed for the expression of FOXP3,OX40,granzyme B(GrB)and perforin(Prf).The proliferating index of the TILs was determined by assessing Ki67 expression.We determined the prognostic value of low and high numbers of TILs on survival by performing Kaplan–Meier analysis using median values as the cut-off points.Except for the number of CD4^(+)FOXP3^(+) regulatory T cells(Tregs)and the CD4/CD8 ratio,none of the CD4^(+),CD8^(+),OX401,GrB^(+) or Prf^(+) TILs were associated with the overall 5-year survival rate.The 5-year survival rate was significantly lower in patients who had a high percentage of Tregs as compared with the those who had a lower percentage(35.3%versus 88.9%,P50.001),while the 5-year survival rate was significantly higher in patients with a high CD4/CD8 ratio as compared with patients who had a low CD4/CD8 ratio(82.4%versus 44.4%,P50.029).When we considered the deaths and surviving cases as separate groups,we found that both the number of CD4^(+) T cells and the CD4/CD8 ratio were significantly lower in patients who died as compared with those who survived(26.33±11.80 versus 47.79±38.18,P=0.023 and 0.60±0.25 versus 1.17±1.02,P=0.019,respectively).In conclusion,decreased proportions of tumor-infiltrating CD4^(+) T cells with high percentages of Tregs and reversed CD4/CD8 ratios were significantly associated with the clinical outcome of patients with cervical carcinoma.

Prognostic value of tumor-infiltrating lymphocyte subtypes in residual tumors of patients with triple-negative breast cancer after neoadjuvant chemotherapy

Background:After neoadjuvant chemotherapy(NAC),non-pathological complete response of breast cancer patients can benefit from tailored adjuvant chemotherapy.However,it is difficult to select patients with poorer prognosis for additional adjuvant chemotherapy to maximize the benefits.Our study aimed to explore whether the subtypes of tumor-infiltrating lymphocytes(TILs)in residual tumors(RT)is related to the prognosis of triple-negative breast cancer(TNBC)after NAC.Methods:Data from patients with primary TNBC consecutively diagnosed at the Breast Disease Center of Peking University First Hospital from 2008 to 2014 were retrieved,and the cases with RT in the breast after NAC were enrolled.TILs subtypes in RT were observed by double-staining immunohistochemistry,and counted with the median TILs value per square millimeter as the cut-off to define high versus low TILs density in each subtype.The relationships between the TIL density of each subgroup and the clinicopathological characteristics of the RT after NAC patients were analyzed by Fisher exact test.Disease-free survival(DFS)and overall survival(OS)were analyzed by the Kaplan-Meier method and log-rank statistics.Results:A total of 37 eligible patients were included in this study,and the median follow-up period was 50 months(range 17–106 months).There was no significant correlation between the infiltrate density of CD4^+,CD8^+,CD20^+,and CD68^+lymphocytes and clinic-pathological characteristics.Significantly better prognosis was observed in patients with high CD4^+-TILs(DFS:P=0.005,OS:P=0.021)and high CD8^+-TILs(DFS:P=0.018)and low CD20^+-TILs(OS:P=0.042).Further analysis showed that patients with CD4^+/CD20^+ratio greater than 1(DFS:P=0.001,OS:P=0.002)or CD8^+/CD20^+ratio greater than 1(DFS:P=0.009,OS:P=0.022)had a better prognosis.Conclusions:Subtypes of TILs in RT is a potential predictive biomarker of survival in TNBC patients after NAC.

Interleukin-18 and -12 synergistically enhance cytotoxic functions of tumor-infiltrating lymphocytes

Background The role of tumor-infiltrating lymphocytes （TILs） in the immunopathogenesis of individual cancer is not clear and is a challenge for anti-tumor immunotherapy. This study aimed to investigate the effects of interleukin （IL）-18 and -12 on cytotoxic functions of TILs, Methods TILs from postoperative gastric cancer patients were costimulated with IL-18 and IL-12. SGC-7g01 tumor cells were pre-incubated with TILs and subcutaneously injected into BALB/C SCID mice. The function of TILs was evaluated by measuring tumor sizes in tumor-bearing mice, T helper （Th）l （tumor necrosis factor （TNF）-a, interferon （IFN）-y） and Th2 cytokine levels （IL-10 and IL-4） in serum and cytotoxicity of mouse natural killer （NK） and CD8＋ T cells. Results IL-18 and IL-12 synergistically inhibited the growth of SGC-7901 cells in vivo and significantly extended the survival rate of SGC-7901-bearing mice （66.7% vs. 13.7%, P 〈0.01）. Moreover, TILs could promote the secretion of TNF-a and IFN-y （（130.34±7.65） vs. （210.63±12.31） pg/ml, P 〈0.01; （14.23±1.97） vs. （30.52±2.12） pg/ml, P 〈0.01）, and downregulate IL-10 and IL-4 secretion （（103.72±11.21）vs. （61.36±5.41） pg/ml, P=0.021; （49.36±4.67）vs. （28.48±3.86） pg/ml, P=0.024）. Conclusion IL-18 and IL-12 can synergistically enhance cytotoxic functions of TILs from human gastric cancer.

The emergence of tumor-infiltrating lymphocytes in nasopharyngeal carcinoma:Predictive value and immunotherapy implications

The clinical study of nasopharyngeal carcinoma(NPC)often reveals a large number of lymphocytes infiltrating the primary tumor site.As an important part of the tumor microenvironment,tumor-infiltrating lymphocytes(TILs)do not exist alone but as a complex multicellular population with high heterogeneity.TILs play an extremely significant role in the occurrence,development,invasion and metastasis of NPC.The latest research shows that they participate in tumorigenesis and treatment,and the composition,quantity,functional status and distribution of TILs subsets have good predictive value for the prognosis of NPC patients.TILs are an independent prognostic factor for TNM stage and significantly correlated with better prognosis.Additionally,adoptive immunotherapy using anti-tumor TILs has achieved good results in a variety of solid tumors including NPC.This review evaluates recent clinical and preclinical studies of NPC,summarizes the role of TILs in promoting and inhibiting tumor growth,evaluates the predictive value of TILs,and explores the potential benefits of TILs-based immunotherapy in the treatment of NPC.

Tertiary lymphoid structures as unique constructions associated with the organization,education,and function of tumor-infiltrating immunocytes

Tertiary lymphoid structures(TLSs)are formations at sites with persistent inflammatory stimulation,including tumors.These ectopic lymphoid organs mainly consist of chemo-attracting B cells,T cells,and supporting dendritic cells(DCs).Mature TLSs exhibit functional organization for the optimal development and collaboration of adaptive immune response,delivering an augmented effect on the tumor microenvironment(TME).The description of the positive correlation between TLSs and tumor prognosis is reliable only under a certain condition involving the localization and maturation of TLSs.Emerging evidence suggests that underlying mechanisms of the anti-tumor effect of TLSs pave the way for novel immunotherapies.Several approaches have been developed to take advantage of intratumoral TLSs,either by combining it with therapeutic agents or by inducing the neogenesis of TLSs.

Persistence of tumor-infiltrating CD8 T cells is tumor-dependent but antigen-independent

How tumor-infiltrating lymphocytes(TILs)that are tumor-specific but functionally tolerant persist in the antigen-expressing tumor tissue is largely unknown.We have previously developed a modified TRansgenic Adenocarcinoma of the Mouse Prostate(TRAMP)model where prostate cancer cells express the T-cell epitope SIYRYYGL(SIY)recognized by CD8 T cells expressing the 2C T-cell receptor(TCR)(referred to as TRP-SIY mice).In TRP-SIY mice,activated 2C T cells rapidly become tolerant following infiltration into the prostate tumor.In this study,we show that tolerant 2C T cells persist in the prostate tumor of TRP-SIY mice by proliferating slowly in a tumor-dependent,but antigen-,interleukin(IL)-7-and IL-15-independent manner.We also show that disappearance of 2C T cells from the lymphoid organs of TRP-SIY mice are due to antigen-induced T-cell contraction rather than altered trafficking or generalized T-cell depletion in the mice.Finally,we show that clonal T cells unreactive to SIY are equally capable of persisting in the prostate tumor.These findings suggest that while functional tolerance of TILs is induced by antigen,persistence of tolerant TILs in the tumor tissue is mediated by a novel mechanism:slow proliferation independent of antigen and homeostatic cytokines.These results also allow CD8 T-cell survival in the tumor environment to be compared with T-cell survival in chronic infection.