Importance of lymph node immune responses in MSI-H/dMMR colorectal cancer

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

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

Phenotypic and spatial heterogeneity of CD8+ tumour infiltrating lymphocytes

CD8+ T cells are the workhorses executing adaptive anti-tumour response, and targets of various cancer immunotherapies. Latest advances have unearthed the sheer heterogeneity of CD8+ tumour infiltrating lymphocytes, and made it increasingly clear that the bulk of the endogenous and therapeutically induced tumour-suppressive momentum hinges on a particular selection of CD8+ T cells with advantageous attributes, namely the memory and stem-like exhausted subsets. A scrutiny of the contemporary perception of CD8+ T cells in cancer and the subgroups of interest along with the factors arbitrating their infiltration contextures, presented herein, may serve as the groundwork for future endeavours to probe further into the regulatory networks underlying their differentiation and migration, and optimise T cell-based immunotherapies accordingly.

Mismatch repair-proficient tumor footprints in the sands of immune desert: mechanistic constraints and precision platforms

Mismatch repair proficient (MMRp) tumors of colorectal origin are one of the prevalent yet unpredictable clinical challenges. Despite earnest efforts, optimal treatment modalities have yet to emerge for this class. The poor prognosis and limited actionability of MMRp are ascribed to a low neoantigen burden and a desert-like microenvironment. This review focuses on the critical roadblocks orchestrated by an immune evasive mechanistic milieu in the context of MMRp. The low density of effector immune cells, their weak spatiotemporal underpinnings, and the high-handedness of the IL-17-TGF-β signaling are intertwined and present formidable challenges for the existing therapies. Microbiome niche decorated by Fusobacterium nucleatum alters the metabolic program to maintain an immunosuppressive state. We also highlight the evolving strategies to repolarize and reinvigorate this microenvironment. Reconstruction of anti-tumor chemokine signaling, rational drug combinations eliciting T cell activation, and reprograming the maladapted microbiome are exciting developments in this direction. Alternative vulnerability of other DNA damage repair pathways is gaining momentum. Integration of liquid biopsy and ex vivo functional platforms provide precision oncology insights. We illustrated the perspectives and changing landscape of MMRp-CRC. The emerging opportunities discussed in this review can turn the tide in favor of fighting the treatment dilemma for this elusive cancer.

Prognostic significance of negative lymph node count in microsatellite instability-high colorectal cancer

BACKGROUND

Microsatellite instability-high (MSI-H) tumors, with elevated tumor mutational burden and expression of neoantigens, represent a distinct immune-activated subpopulation in colorectal cancer (CRC), characterized by strong lymph node reaction, locally advanced tumor and higher total lymph nodes harvested (TLN), but less metastatic lymph nodes and fewer incidence of III-IV stage. Host immune response to tumor and lymph nodes may be an important prognostic factor. However, N stage and LNR (Lymph-Node Ratio) have limitations in predicting the prognosis of MSI-H patients. Negative lymph node count (NLC) provided a more precise representation of immune activation status and extent of tumor metastasis. The study aims to detect prognostic significance of NLC in MSI-H CRC patients, and compare it with N stage, TLN and LNR.

METHODS

Retrospective data of 190 consecutive MSI-H CRC patients who received curative resection were collected. Survival analyses were performed using the Kaplan-Meier method. Clinicopathological variables including NLC, N stage, TLN and LNR were studied in univariate and multivariate COX regression analyses. ROC (receiver operating characteristic curve) and concordance index were employed to compare the differences in predictive efficacy between NLC, N stage, TLN and LNR.

RESULTS

Patients with increased NLC experienced a significantly improved 5-years DFS and OS in Kaplan-Meier analysis, univariate analysis, and multivariate analysis, independent of potential confounders examined. Increased NLC corresponded to elevated 5-years DFS rate and 5-years OS rate. AUC (area under curve) and concordance index of NLC in DFS and OS predicting were both significantly higher than N stage, TLN and LNR.

CONCLUSIONS

Negative lymph node is an important independent prognostic factor for MSI-H patients. Reduced NLC is associated with tumor recurrence and poor survival, which is a stronger prognostic factor than N stage, TLN and LNR.

Prognostic and predictive value of examined lymph node count in stage III colorectal cancer: a population based study

BACKGROUND

The role of tumor-draining lymph nodes in the progression of malignant tumors, including stage III colorectal cancer (CRC), is critical. However, the prognostic and predictive value of the number of examined lymph nodes (ELNs) are not fully understood.

METHODS

This population-based study retrospectively analyzed data from 106,843 patients with stage III CRC who underwent surgical treatment and registered in three databases from 2004 to 2021. The Surveillance, Epidemiology, and End Results (SEER) cohort was divided using into training and test cohorts at a ratio of 3:2. We employed restricted cubic spline (RCS) curves to explore nonlinear relationships between overall survival (OS) and ELNs counts and performed Cox regression to evaluate hazard ratios across different ELNs count subtypes. Additional validation cohorts were utilized from the First Affiliated Hospital, Sun Yat-sen University and The Cancer Genome Atlas (TCGA) under the same criteria. Outcomes measured included OS, cancer-specific survival (CSS), and progression-free survival (PFS). Molecular analyses involved differential gene expression using the "limma" package and immune profiling through CIBERSORT. Tissue microarray slides and multiplex immunofluorescence (MIF) were used to assess protein expression and immune cell infiltration.

RESULTS

Patients with higher ELNs counts (≥ 17) demonstrated significantly better long-term survival outcomes across all cohorts. Enhanced OS, CSS, and PFS were notably evident in the LN-ELN group compared to those with fewer ELNs. Cox regression models underscored the prognostic value of higher ELNs counts across different patient subgroups by age, sex, tumor differentiation, and TNM stages. Subtype analysis based on ELNs count revealed a marked survival benefit in patients treated with adjuvant chemotherapy in the medium and large ELNs counts (≥ 12), whereas those with fewer ELNs showed negligible benefits. RNA sequencing and MIF indicated elevated immune activation in the LN-ELN group, characterized by increased CD3+, CD4+, and CD8 + T cells within the tumor microenvironment.

CONCLUSIONS

The number of ELNs independently predicts survival and the immunological landscape at the tumor site in stage III CRC, underscoring its dual prognostic and predictive value.

Survival analysis in pT1-3 and paracolic lymph-node invasion colorectal cancer: the prognostic role of positive paracolic lymph-node ratio for adjuvant chemotherapy

PURPOSE

Several studies have observed that some stage III colorectal cancer (CRC) patients cannot benefit from standard adjuvant chemotherapy. However, there is no unified screening standard to date.

METHODS

Consecutive patients with pathologically confirmed colon adenocarcinoma treated in 3 centers between January 2016 and December 2018 were included. Patients were divided into four groups according to different stages and positive paracolic lymph-node ratio (P-LNR) [Cohort 1: pT1-3N0M0, Cohort 2: pT1-3N + (P-LNR ≤ 0.15)M0, Cohort 3: pT4N0M0, Cohort 4: stage III patients except for pT1-3N + (P-LNR ≤ 0.15)M0], and further overall survival was compared by Kaplan-Meier method. The univariate and multivariate analyses were employed for cox proportional hazards model.

RESULTS

We retrospectively reviewed 5581 consecutive CRC patients with, and 2861 eligible patients were enrolled for further analysis. The optimal cut-off value of P-LNR in our study was 0.15. There was no significant difference in OS (91.36 vs. 93.74%) and DFS (87.65 vs. 90.96%) between stage III patients with pT1-3N + (P-LNR ≤ 0.15)M0 and those with pT1-3N0M0. Further analysis demonstrated that CRC patients with pT1-3N + (P-LNR ≤ 0.15)M0 were less likely to benefit from 8 cycles of CAPOX or FOLFOX chemotherapy and suffered fewer adverse events from declining chemotherapy. Comparing with 0-4 cycles versus 8 cycles, the overall survival rates were 91.35 versus 90.19% (P = 0.79), and with a DFS of 87.50 versus 88.24% (P = 0.49), the duration of adjuvant chemotherapy was not an independent risk factor for patients with pT1-3N + (P-LNR ≤ 0.15)M0 (HR: 0.70, 95% CI 0.90-1.30, P = 0.42).

CONCLUSION

The concept of P-LNR we proposed might have a high clinical application value and accurately enable clinicians to screen out specific CRC patients who decline or prefer limited chemotherapy.

TRIAL REGISTRY

The clinical trial registration number: ChiCTR2300076883.

Tumor-draining lymph nodes: opportunities, challenges, and future directions in colorectal cancer immunotherapy

Tumor-draining lymph nodes (TDLNs) are potential immunotherapy targets that could expand the population of patients with colorectal cancer (CRC) who may benefit from immunotherapy. Currently, pathological detection of tumor cell infiltration limits the acquisition of immune information related to the resected lymph nodes. Understanding the immune function and metastatic risk of specific stages of lymph nodes can facilitate better discussions on the removal or preservation of lymph nodes, as well as the timing of immunotherapy. This review summarized the contribution of TDLNs to CRC responses to immune checkpoint blockade therapy, local immunotherapy, adoptive cell therapy, and cancer vaccines, and discussed the significance of these findings for the development of diagnostics based on TDLNs and the potential implications for guiding immunotherapy after a definitive diagnosis. Molecular pathology and immune spectrum diagnosis of TDLNs will promote significant advances in the selection of immunotherapy options and predicting treatment efficacy.

Enlarged tumour-draining lymph node with immune-activated profile predict favourable survival in non-metastatic colorectal cancer

BACKGROUND

The tumour-draining lymph node (TDLN) plays a pivotal role in the suppression of malignant tumour, however, the immunological profile and prognostic differences between large TDLN (L-TDLN) and small TDLN (S-TDLN) in colorectal cancer (CRC) remain unclear.

METHODS

We conducted a study using data from the Chinese National Cancer Center (CNCC) database, identifying 837 CRC patients with non-metastatic TDLN, and categorised them into L-TDLN and S-TDLN groups. The long-term survival outcomes and adjuvant therapy efficacy were compared between the two groups. Furthermore, we evaluated the differences in immune activation status and immune cell subsets between patients in L-TDLN and S-TDLN groups by RNA sequencing and immunohistochemical (IHC) staining.

RESULTS

Patients with L-TDLN demonstrated better long-term outcomes compared to those with S-TDLN. Among patients with L-TDLN, there was no significant difference in long-term outcomes between those who received adjuvant chemotherapy and those who did not. The RNA sequencing data revealed a wealth of immune-activating pathways explored in L-TDLN. Furthermore, IHC analysis demonstrated higher numbers of CD3+ and CD8 + T cells in L-TDLN and the corresponding CRC lesions, as compared to patients with S-TDLN.

CONCLUSION

Enlarged TDLN exhibited an activated anti-tumour immune profile and may serve as an indicator for favourable survival in non-metastatic CRC.

Preoperative contrast-enhanced CT imaging and clinicopathological characteristics analysis of mismatch repair-deficient colorectal cancer

BACKGROUND

Colorectal cancer (CRC) can develop through various pathogenetic pathways, and one of the primary pathways is high microsatellite instability (MSI-H)/deficient mismatch repair (dMMR). This study investigated the correlation between preoperative contrast-enhanced CT (CECT) and clinicopathologic characteristics of colorectal cancer (CRC) according to different mismatch repair (MMR) statuses.

METHODS

From April 2021 to July 2022, a total of 281 CRC patients with preoperative CECT and available MMR status were enrolled from a single centre for this retrospective study. Preoperative CECT features and clinicopathologic characteristics were analysed. Univariate and multivariate logistic regression analyses were used for statistical analysis. A nomogram was established based on the multivariate logistic regression results. Preoperative and postoperative dynamic nomogram prediction models were established. The C-index, a calibration plot, and clinical applicability of the two models were evaluated, and internal validation was performed using three methods.

RESULTS

In total, 249 patients were enrolled in the proficient mismatch repair (pMMR) group and 32 patients in the deficient mismatch repair (dMMR) group. In multivariate analysis, tumour location (right-hemi colon vs. left-hemi colon, odds ratio (OR) = 2.90, p = .036), the hypoattenuation-within-tumour ratio (HR) (HR > 2/3 vs. HR < 1/3, OR = 36.7, p < .001; HR 1/3-2/3 vs. HR < 1/3, OR = 6.05, p = .031), the number of lymph nodes with long diameter ≥ 8 mm on CECT (OR = 1.32, p = .01), CEA status (CEA positive vs. CEA negative, OR = 0.07, p = .002) and lymph node metastasis (OR = 0.45, p = .008) were independent risk factors for dMMR. Pre- and postoperative C-statistic were 0.861 and 0.908, respectively.

CONCLUSION

The combination of pre-operative CECT and clinicopathological characteristics of CRC correlates with MMR status, providing possible non-invasive MMR prediction. Particularly for dMMR CRC, tumour-draining lymph node status should be prudently evaluated by CECT.

Lymph node metastasis in cancer progression: molecular mechanisms, clinical significance and therapeutic interventions

Lymph nodes (LNs) are important hubs for metastatic cell arrest and growth, immune modulation, and secondary dissemination to distant sites through a series of mechanisms, and it has been proved that lymph node metastasis (LNM) is an essential prognostic indicator in many different types of cancer. Therefore, it is important for oncologists to understand the mechanisms of tumor cells to metastasize to LNs, as well as how LNM affects the prognosis and therapy of patients with cancer in order to provide patients with accurate disease assessment and effective treatment strategies. In recent years, with the updates in both basic and clinical studies on LNM and the application of advanced medical technologies, much progress has been made in the understanding of the mechanisms of LNM and the strategies for diagnosis and treatment of LNM. In this review, current knowledge of the anatomical and physiological characteristics of LNs, as well as the molecular mechanisms of LNM, are described. The clinical significance of LNM in different anatomical sites is summarized, including the roles of LNM playing in staging, prognostic prediction, and treatment selection for patients with various types of cancers. And the novel exploration and academic disputes of strategies for recognition, diagnosis, and therapeutic interventions of metastatic LNs are also discussed.

Macroscopic Evaluation of Colon Cancer Resection Specimens

Colon cancer is a common disease internationally. Outcomes have not improved to the same degree as in rectal cancer, where the focus on total mesorectal excision and pathological feedback has significantly contributed to improved survival and reduced local recurrence. Colon cancer surgery shows significant variation around the world, with differences in mesocolic integrity, height of the vascular ligation and length of the bowel resected. This leads to variation in well-recognised quality measures like lymph node yield. Pathologists are able to assess all of these variables and are ideally placed to provide feedback to surgeons and the wider multidisciplinary team to improve surgical quality over time. With a move towards complete mesocolic excision with central vascular ligation to remove the primary tumour and all mechanisms of spread within an intact package, pathological feedback will be central to improving outcomes for patients with operable colon cancer. This review focusses on the key quality measures and the evidence that underpins them.

Efficacy of Immune Checkpoint Inhibition and Cytotoxic Chemotherapy in Mismatch Repair-Deficient and Microsatellite Instability-High Pancreatic Cancer: Mayo Clinic Experience

PURPOSE

Pancreatic cancer (PC) carries a poor prognosis with high rates of unresectable/metastatic disease at diagnosis, recurrence after resection, and few systemic therapy options. Deficient mismatch repair (dMMR)/high microsatellite instability (MSI-H) PCs demonstrated uncharacteristically poor outcomes in KEYNOTE-158, evaluating pembrolizumab in MSI-H solid tumors. Our study aggregates the Mayo Clinic experience with dMMR/MSI-H PCs, characterizing the clinical, molecular, and treatment response patterns with a focus on response to immune checkpoint inhibitors (ICIs).

METHODS

Retrospective data were collected from the electronic medical record from December 2009 to February 2023. Patients were included if they had a pathologically confirmed pancreatic malignancy and had (1) deficient expression of mismatch repair (MMR) proteins by tumor immunohistochemistry, (2) pathogenic mutation of MMR genes on genomic sequencing, and/or (3) MSI-H by polymerase chain reaction.

RESULTS

Thirty-two patients were identified for inclusion, with all stages of disease represented. Sixteen of these patients underwent surgery or chemoradiotherapy. Of these patients, uncharacteristically favorable responses were seen, with a recurrence rate of only 19% (n = 3) despite a median follow-up of 25 months. In the palliative setting, excellent responses to ICI were seen, with overall response rate (ORR) of 75% (20% complete response). Median time to disease progression was not reached. Response rates to cytotoxic chemotherapy in the palliative setting were poor, with 30% ORR and median time to progression of 4 months. We observed a high rate of discrepancy between MMR and MSI testing methods, representing 19% of the entire cohort and 26% of evaluable cases.

CONCLUSION

Our data argue for the preferential use of ICI over cytotoxic chemotherapy in any patient with dMMR/MSI-H PC requiring systemic therapy, including in the metastatic and adjuvant/neoadjuvant settings.

Dynamics and specificities of T cells in cancer immunotherapy

Recent advances in cancer immunotherapy - ranging from immune-checkpoint blockade therapy to adoptive cellular therapy and vaccines - have revolutionized cancer treatment paradigms, yet the variability in clinical responses to these agents has motivated intense interest in understanding how the T cell landscape evolves with respect to response to immune intervention. Over the past decade, the advent of multidimensional single-cell technologies has provided the unprecedented ability to dissect the constellation of cell states of lymphocytes within a tumour microenvironment. In particular, the rapidly expanding capacity to definitively link intratumoural phenotypes with the antigen specificity of T cells provided by T cell receptors (TCRs) has now made it possible to focus on investigating the properties of T cells with tumour-specific reactivity. Moreover, the assessment of TCR clonality has enabled a molecular approach to track the trajectories, clonal dynamics and phenotypic changes of antitumour T cells over the course of immunotherapeutic intervention. Here, we review the current knowledge on the cellular states and antigen specificities of antitumour T cells and examine how fine characterization of T cell dynamics in patients has provided meaningful insights into the mechanisms underlying effective cancer immunotherapy. We highlight those T cell subsets associated with productive T cell responses and discuss how diverse immunotherapies might leverage the pre-existing tumour-reactive T cell pool or instruct de novo generation of antitumour specificities. Future studies aimed at elucidating the factors associated with the elicitation of productive antitumour T cell immunity are anticipated to instruct the design of more efficacious treatment strategies.

Para-Aortic Lymph Node Dissection for Patients with Node-Negative Cervical Squamous Cell Carcinoma: A Retrospective Cohort Study

Objective. The current guidelines for cervical cancer are uncertain regarding whether the para-aortic lymph nodes (PALNs) need to be removed. For patients with negative PALNs, whether the addition of PALN dissection (PALND) can be translated into survival benefits is unknown. Methods. The medical records of 3,995 patients with FIGO stage IB-IIA cervical squamous cell carcinoma (CSCC) who underwent abdominal radical surgery between 2006 and 2014 at our center were retrospectively reviewed. Two groups were identified: PALN-negative patients who underwent PALND (+PALND) and those who did not (−PALND). The groups were matched by propensity score matching (PSM). Survival was analyzed using the Kaplan–Meier method and the Cox proportional hazards model. Subgroups were stratified by the variables known at the time of diagnosis. Results. After PSM, 313 patients were matched to the −PALND (cohort 1) and +PALND (cohort 2) groups. Cohort 2 patients had a poorer prognosis than cohort 1 patients in terms of overall survival (OS, $P=0.014$ ), and PALND was an independent prognostic factor for OS ( $P=0.021$ ). There were no differences in recurrence patterns between the groups. Subgroup analysis showed that cohort 2 patients had worse OS than cohort 1 patients when they were aged ≤47 years ( $P=0.033$ ), were premenopausal ( $P=0.032$ ), were in stage IB ( $P=0.009$ ), or had preoperative SCC-Ag<6.5 ( $P=0.009$ ). Conclusions. PALND negatively impacts OS in early-stage PALN-negative CSCC patients. For CSCC patients who are clinically PALN-negative, especially those who are young, are premenopausal, have tumors confined to the cervix, and have relatively low SCC-Ag values, PALND may “rub salt on the wound.”

Fecal microbiota in patients with a stoma decreases anaerobic bacteria and alters taxonomic and functional diversities

Colorectal cancer (CRC) is one of the most common malignant diseases. Generally, stoma construction is performed following surgery for the resection of the primary tumor in patients with CRC. The association of CRC with the gut microbiota has been widely reported, and the gut microbiota is known to play an important role in the carcinogenesis, progression, and treatment of CRC. In this study, we compared the microbiota of patients with CRC between with and without a stoma using fecal metagenomic sequencing data from SCRUM-Japan MONSTAR-SCREEN, a joint industry-academia cancer research project in Japan. We found that the composition of anaerobes was reduced in patients with a stoma. In particular, the abundance of Alistipes, Akkermansia, Intestinimonas, and methane-producing archaea decreased. We also compared gene function (e.g., KEGG Orthology and KEGG pathway) and found that gene function for methane and short-chain fatty acids (SCFAs) production was underrepresented in patients with a stoma. Furthermore, a stoma decreased Shannon diversity based on taxonomic composition but increased that of the KEGG pathway. These results suggest that the feces of patients with a stoma have a reduced abundance of favorable microbes for cancer immunotherapy. In conclusion, we showed that a stoma alters the taxonomic and functional profiles in feces and may be a confounding factor in fecal microbiota analysis.

Colon cancer microsatellite instability influences computed tomography assessment of regional lymph node morphology and diagnostic performance

PURPOSE

To elucidate whether a high level of microsatellite instability (MSI-high) in colon cancer influences the CT assessment of regional lymph node (rLN) morphology and diagnostic performance on predicting pathological node-negative (pN0) patients.

METHOD

We retrospectively reviewed 507 patients with cecal/proximal ascending colon cancer (age, 63.0 ± 11.6 years; MSI-stable, n = 398; MSI-high, n = 109) who underwent right hemicolectomy between July 1, 2009, and December 31, 2018. Preoperative CT images were assessed for number of rLNs, long/short diameter of the largest rLN, and CT LN grade (CTN0, low probability of metastasis; CTN1, borderline; CTN2, high probability). Sensitivity, specificity, positive predictive value and negative predictive value for predicting pN0 was calculated. Multivariable logistic regression analysis was performed. Statistical significance was defined as P < 0.05.

RESULTS

A study population of 507 patients (mean age ± standard deviation, 63.0 ± 11.6; 264 women) were evaluated. In patients with rLN metastasis, the rLN long axis (pN1: P = 0.013, pN2: P = 0.039) and short axis (pN1: P = 0.001, pN2: P = 0.009) were both longer in MSI-high tumors compared with MSI-stable tumors. High specificity for predicting pN0 was only achieved in MSI-high tumors [sensitivity_MSI-stable = 58.3% (n = 137/235), specificity_MSI-stable = 71.2% (n = 116/163); sensitivity_MSI-high = 38.4% (n = 33/86), specificity_MSI-high = 91.3% (n = 21/23)]. Multivariable logistic regression indicated MSI-high (P < 0.001, odds ratio = 3.701), smaller LN long axis (P = 0.023, odds ratio = 0.905), and lower CT LN grade (CTN0: P = 0.009, odds ratio = 2.987; CTN1: P = 0.014, odds ratio = 2.195) as significant parameters in predicting pN0.

CONCLUSION

MSI-high colon cancer is associated with larger rLNs and high specificity for predicting pN0 on CT assessment.

Lymphocytes in tumor-draining lymph nodes co-cultured with autologous tumor cells for adoptive cell therapy

Background

Tumor-draining lymph nodes (TDLNs) are primary sites, where anti-tumor lymphocytes are primed to tumor-specific antigens and play pivotal roles in immune responses against tumors. Although adoptive cell therapy (ACT) using lymphocytes isolated from TDLNs were reported, characterization of immune activity of lymphocytes in TDLNs to tumor cells was not comprehensively performed. Here, we demonstrate TDLNs to have very high potential as cell sources for immunotherapy.

Methods

Lymphocytes from TDLNs resected during surgical operation were cultured with autologous-tumor cells for 2 weeks and evaluated tumor-reactivity by IFNγ ELISPOT assay. We investigated the commonality of T cell receptor (TCR) clonotypes expanded by the co-culture with tumor cells with those of tumor infiltrating lymphocytes (TILs).

Results

We found that that TCR clonotypes of PD-1-expressing CD8⁺ T cells in lymph nodes commonly shared with those of TILs in primary tumors and lymphocytes having tumor-reactivity and TCR clonotypes shared with TILs could be induced from non-metastatic lymph nodes when they were co-cultured with autologous tumor cells.

Conclusion

Our results imply that tumor-reactive effector T cells were present even in pathologically non-metastatic lymph nodes and could be expanded in vitro in the presence of autologous tumor cells and possibly be applied for ACT.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12967-022-03444-1.

Lymph Nodes as Anti-Tumor Immunotherapeutic Tools: Intranodal-Tumor-Specific Antigen-Pulsed Dendritic Cell Vaccine Immunotherapy

Simple Summary

In the field of cancer therapy, lymph nodes are important not only as targets for metastases resection but also as prudent target organs for cancer immunotherapy. Lymph nodes comprise a complete structure for the accumulation of a large number of T cells and their distribution throughout the body after antigen presentation and activation of dendritic cells. This review highlights current topics on the importance of lymph node structure in antitumor immunotherapy and intranodal-antigen-presenting mature dendritic cell vaccine therapy. We also discuss the rationale behind intranodal injection methods and their applications in neoantigen vaccine therapy, a new cancer immunotherapy.

Abstract

Hundreds of lymph nodes (LNs) are scattered throughout the body. Although each LN is small, it represents a complete immune organ that contains almost all types of immunocompetent and stromal cells functioning as scaffolds. In this review, we highlight the importance of LNs in cancer immunotherapy. First, we review recent reports on structural and functional properties of LNs as sites for antitumor immunity and discuss their therapeutic utility in tumor immunotherapy. Second, we discuss the rationale and background of ultrasound (US)-guided intranodal injection methods. In addition, we review intranodal administration therapy of tumor-specific-antigen-pulsed matured dendritic cells (DCs), including neoantigen-pulsed vaccines.

Revealing Clonal Responses of Tumor-Reactive T-Cells Through T Cell Receptor Repertoire Analysis

CD8⁺ T cells are the key effector cells that contribute to the antitumor immune response. They comprise various T-cell clones with diverse antigen-specific T-cell receptors (TCRs). Thus, elucidating the overall antitumor responses of diverse T-cell clones is an emerging challenge in tumor immunology. With the recent advancement in next-generation DNA sequencers, comprehensive analysis of the collection of TCR genes (TCR repertoire analysis) is feasible and has been used to investigate the clonal responses of antitumor T cells. However, the immunopathological significance of TCR repertoire indices is still undefined. In this review, we introduce two approaches that facilitate an immunological interpretation of the TCR repertoire data: inter-organ clone tracking analysis and single-cell TCR sequencing. These approaches for TCR repertoire analysis will provide a more accurate understanding of the response of tumor-specific T cells in the tumor microenvironment.

PD-1 blockade therapy promotes infiltration of tumor-attacking exhausted T cell clonotypes

PD-1 blockade exerts clinical efficacy against various types of cancer by reinvigorating T cells that directly attack tumor cells (tumor-specific T cells) in the tumor microenvironment (TME), and tumor-infiltrating lymphocytes (TILs) also comprise nonspecific bystander T cells. Here, using single-cell sequencing, we show that TILs include skewed T cell clonotypes, which are characterized by exhaustion (T_ex) or nonexhaustion signatures (T_non-ex). Among skewed clonotypes, those in the T_ex, but not those in the T_non-ex, cluster respond to autologous tumor cell lines. After PD-1 blockade, non-preexisting tumor-specific clonotypes in the T_ex cluster appear in the TME. Tumor-draining lymph nodes (TDLNs) without metastasis harbor a considerable number of such clonotypes, whereas these clonotypes are rarely detected in peripheral blood. We propose that tumor-infiltrating skewed T cell clonotypes with an exhausted phenotype directly attack tumor cells and that PD-1 blockade can promote infiltration of such T_ex clonotypes, mainly from TDLNs.