Sentinel node lymphocytes: tumour reactive lymphocytes identified intraoperatively for the use in immunotherapy of colon cancer

Precision Medicine for Colorectal Cancer with Liquid Biopsy and Immunotherapy

Simple Summary

There are some challenges to improve the clinical outcome of colorectal cancers (CRCs) by implementing new technologies, such as early detection of recurrence/relapse and selection of appropriate drugs based on the genomic profiles of tumors. For example, the genomic characteristics of tumors can be analyzed by blood-based tests, namely ‘liquid biopsies’, which are minimally-invasive and can be performed repeatedly during the treatment course. Hence, liquid biopsies are considered to hold great promise to fill these gaps in clinical routines. In this review, we addressed clinical usefulness of liquid biopsies in the clinical management of CRC patients, including cancer screening, detection of minimal residual disease, selection of appropriate molecular-targeted drugs, monitoring of the treatment responsiveness, and very early detection of recurrence/relapse of the disease. Furthermore, we discussed the possibility of adoptive T cell therapies and a future personalized immunotherapy based on tumor genome information.

Abstract

In the field of colorectal cancer (CRC) treatment, diagnostic modalities and chemotherapy regimens have progressed remarkably in the last two decades. However, it is still difficult to identify minimal residual disease (MRD) necessary for early detection of recurrence/relapse of tumors and to select and provide appropriate drugs timely before a tumor becomes multi-drug-resistant and more aggressive. We consider the leveraging of in-depth genomic profiles of tumors as a significant breakthrough to further improve the overall prognosis of CRC patients. With the recent technological advances in methodologies and bioinformatics, the genomic profiles can be analyzed profoundly without delay by blood-based tests—‘liquid biopsies’. From a clinical point of view, a minimally-invasive liquid biopsy is thought to be a promising method and can be implemented in routine clinical settings in order to meet unmet clinical needs. In this review, we highlighted clinical usefulness of liquid biopsies in the clinical management of CRC patients, including cancer screening, detection of MRD, selection of appropriate molecular-targeted drugs, monitoring of the treatment responsiveness, and very early detection of recurrence/relapse of the disease. In addition, we addressed a possibility of adoptive T cell therapies and a future personalized immunotherapy based on tumor genome information.

Immune responses against autologous tumor and human papilloma virus in lymph nodes from patients with penile cancer

Purpose

Nearly half of penile cancers are related to human papillomavirus (HPV) infection. Investigations of tumor- and HPV-specific T cell reactivity in regional lymph nodes (LNs) from patients with penile cancer are warranted.

Materials and Methods

In this study, single-cell suspensions from LNs and peripheral blood from 11 patients with penile cancer were stained with antibodies for lymphocyte markers and analyzed by fluorescence-activated cell sorting (FACS). DNA was extracted from the tumor tissue and HPV status was investigated by PCR.

Results

T-cell reactivity against autologous tumor-extract and against the HPV-vaccine Gardasil® was tested by flow-cytometric assay of specific cell-mediated immune response in activated whole blood (FASCIA). CD4⁺/CD8⁺ ratios were significantly lower in HPV positive LNs (p<0.05). Immune responses to tumor extract assessed by blast transformation and expansion in vitro, of either CD4⁺ or CD8⁺ T-cells, were found in 9 of 13 LNs (69%). 5 of 6 tested patients demonstrated T cell recognition of tumor-associated antigen(s). In HPV-positive patients, dose-dependent T cell responses against L1 (late) HPV proteins (Gardasil vaccine) were demonstrated.

Conclusions

LN-derived T cells from patients with penile cancer recognize tumor antigen(s) and in HPV-positive cases, there is a response against L1 (late) HPV proteins, being constituents of the Gardasil vaccine.

Advances in cancer immunotherapy 2019 - latest trends

Immunotherapy has become an established pillar of cancer treatment improving the prognosis of many patients with a broad variety of hematological and solid malignancies. The two main drivers behind this success are checkpoint inhibitors (CPIs) and chimeric antigen receptor (CAR) T cells. This review summarizes seminal findings from clinical and translational studies recently presented or published at important meetings or in top-tier journals, respectively. For checkpoint blockade, current studies focus on combinational approaches, perioperative use, new tumor entities, response prediction, toxicity management and use in special patient populations. Regarding cellular immunotherapy, recent studies confirmed safety and efficacy of CAR T cells in larger cohorts of patients with acute lymphoblastic leukemia or diffuse large B cell lymphoma. Different strategies to translate the striking success of CAR T cells in B cell malignancies to other hematological and solid cancer types are currently under clinical investigation. Regarding the regional distribution of registered clinical immunotherapy trials a shift from PD-1 / PD-L1 trials (mainly performed in the US and Europe) to CAR T cell trials (majority of trials performed in the US and China) can be noted.

TCR sequencing analysis of cancer tissues and tumor draining lymph nodes in colorectal cancer patients

Tumor draining lymph nodes (TDLNs) are located in the routes of lymphatic drainage from a primary tumor and have the highest risk of metastasis in various types of solid tumors. TDLNs are also considered as a tissue to activate the antitumor immunity, where antigen-specific effector T cells are generated. However, T cell receptor (TCR) repertoires in TDLNs have not been well characterized. We collected 23 colorectal cancer tumors with 203 lymph nodes with/without metastatic cancer cells (67 were metastasis-positive and the remaining 136 were metastasis-negative) and performed TCR sequencing. Metastasis-positive TDLNs showed a significantly lower TCR diversity and shared TCR clonotypes more frequently with primary tumor tissues compared to metastasis-negative TDLNs. Principal component analysis indicated that TDLNs with metastasis showed similar TCR repertoires. These findings suggest that cancer-reactive T cell clones could be enriched in the metastasis-positive TDLNs.

Adoptive Cell Transfer: Is it a Promising Immunotherapy for Colorectal Cancer?

The last decade has witnessed significant advances in the adoptive cell transfer (ACT) technique, which has been appreciated as one of the most promising treatments for patients with cancer. Utilization of ACT can enhance the function of the immune system or improve the specificity and persistence of transferred cells. Various immune cells including T lymphocytes, natural killer cells, dendritic cells, and even stem cells can be used in the ACT despite their different functional mechanisms. Colorectal cancer (CRC) is among the most common malignancies and causes millions of deaths worldwide every year. In this review, we discuss the status and perspective of the ACT in the treatment of CRC.

Increased CD4+ T cell lineage commitment determined by CpG methylation correlates with better prognosis in urinary bladder cancer patients

Background

Urinary bladder cancer is a common malignancy worldwide. Environmental factors and chronic inflammation are correlated with the disease risk. Diagnosis is performed by transurethral resection of the bladder, and patients with muscle invasive disease preferably proceed to radical cystectomy, with or without neoadjuvant chemotherapy. The anti-tumour immune responses, known to be initiated in the tumour and draining lymph nodes, may play a major role in future treatment strategies. Thus, increasing the knowledge of tumour-associated immunological processes is important. Activated CD4⁺ T cells differentiate into four main separate lineages: Th1, Th2, Th17 and Treg, and they are recognized by their effector molecules IFN-γ, IL-13, IL-17A, and the transcription factor Foxp3, respectively. We have previously demonstrated signature CpG sites predictive for lineage commitment of these four major CD4⁺ T cell lineages. Here, we investigate the lineage commitment specifically in tumour, lymph nodes and blood and relate them to the disease stage and response to neoadjuvant chemotherapy.

Results

Blood, tumour and regional lymph nodes were obtained from patients at time of transurethral resection of the bladder and at radical cystectomy. Tumour-infiltrating CD4⁺ lymphocytes were significantly hypomethylated in all four investigated lineage loci compared to CD4⁺ lymphocytes in lymph nodes and blood (lymph nodes vs tumour-infiltrating lymphocytes: IFNG -4229 bp p < 0.0001, IL13 -11 bp p < 0.05, IL17A -122 bp p < 0.01 and FOXP3 -77 bp p > 0.05). Examination of individual lymph nodes displayed different methylation signatures, suggesting possible correlation with future survival. More advanced post-cystectomy tumour stages correlated significantly with increased methylation at the IFNG -4229 bp locus. Patients with complete response to neoadjuvant chemotherapy displayed significant hypomethylation in CD4⁺ T cells for all four investigated loci, most prominently in IFNG p < 0.0001. Neoadjuvant chemotherapy seemed to result in a relocation of Th1-committed CD4⁺ T cells from blood, presumably to the tumour, indicated by shifts in the methylation patterns, whereas no such shifts were seen for lineages corresponding to IL13, IL17A and FOXP3.

Conclusion

Increased lineage commitment in CD4⁺ T cells, as determined by demethylation in predictive CpG sites, is associated with lower post-cystectomy tumour stage, complete response to neoadjuvant chemotherapy and overall better outcome, suggesting epigenetic profiling of CD4⁺ T cell lineages as a useful readout for clinical staging.

Electronic supplementary material

The online version of this article (10.1186/s13148-018-0536-6) contains supplementary material, which is available to authorized users.

Sentinel node detection in muscle-invasive urothelial bladder cancer is feasible after neoadjuvant chemotherapy in all pT stages, a prospective multicenter report

PURPOSE

To determine whether sentinel node detection (SNd) in muscle-invasive urothelial bladder cancer (MIBC) can be performed in patients undergoing neoadjuvant chemotherapy (NAC) and determine whether SNd is feasible in all pT stages, including pT0.

BACKGROUND

Previous published series of SNd in MIBC have not included patients undergoing NAC, and systematic reports of pT0 patients w/wo NAC were absent. Translational immunological tumor research on MIBC focusing on SNd, in the era of NAC, requires technical feasibility. Additionally, SNd in MIBC requests further evaluations as a method for nodal staging.

MATERIALS AND METHODS

Ninety-nine patients with suspected urothelial MIBC were prospectively selected from six urological centers. After TUR-B and primary staging, 65 MIBC patients qualified for radical cystectomy. Precystectomy staging was cT2a-T4aN0M0, including 47 NAC patients and 18 chemo-naïve patients. All 65 patients underwent intraoperative SNd by peritumoral injection of 80 Mbq Technetium and Geiger probe detection. Postcystectomy staging was pT0-T4aN0-N2M0. SNs were defined by two calculations, SNdef1 and SNdef2.

RESULTS

Totally 1063 lymph nodes were removed (total SNs; 222-227). NAC patients with pT0 (n = 24) displayed a true positive detection in 91.7 % by either SNdef, with a median of 3.0 SNs. NACpT >0 patients had a true positive detection in 87 % (SNdef1) and 91.3 % (SNdef2). In a univariate analysis, patient group neither NAC nor tumor downstaging influenced detection rates, regardless of SN definition. In total eight patients, 4/22 metastatic nodes were SNs while 18/22 were non-SNs.

CONCLUSIONS

Sentinel node detection in MIBC is feasible also in NAC patients, regardless of pT stage. SNd played no role in nodal staging.

Detection of micrometastases by flow cytometry in sentinel lymph nodes from patients with renal tumours

BACKGROUND

Stage is an important prognostic factor in renal tumours and dissemination to regional lymph nodes is associated with poor outcomes. Lymph nodes are routinely assessed by immunohistochemistry and microscopic evaluation, a time-consuming process where micrometastases might go undiagnosed. We evaluate an alternative method for detecting metastatic cells in sentinel nodes (SNs) by flow cytometry.

METHODS

A total of 15 nodes from 5 patients diagnosed with renal tumours were analysed by flow cytometry. Staining for the intracellular marker cytokeratin 18 (CK18) with the surface markers carbonic anhydrase IX (CA9) and Cadherin 6 were used in flow cytometry analysis. Peripheral blood mononuclear cells (PBMCs) with the addition of known concentrations of cancer cell lines were analysed to investigate the sensitivity of micrometastasis detection.

RESULTS

Stability of the assay was marked by low intra-assay variability (coefficient of variance ⩽16%) and low inter-assay variability (R²=0.9996-1). Eight nodes in four patients were positive for metastasis; six of them were considered being micrometastatic. These metastases were undetected by routine pathology and the patients were restaged from pN0 to pN1.

CONCLUSIONS

Flow cytometry is able to detect micrometastases in lymph nodes of renal tumour patients that were undetected under H&E examination.

Pilot study of adoptive immunotherapy with sentinel node-derived T cells in muscle-invasive urinary bladder cancer

OBJECTIVE

The aim of this study was to determine by computed tomography (CT) whether treatment with tumor-draining lymph-node-derived expanded autologous T lymphocytes results in objective responses and/or improved survival in patients with metastatic urinary bladder cancer (UBC) and to record the toxicity of the treatment.

MATERIALS AND METHODS

Eighteen patients with metastatic UBC were prospectively selected from two centers. The preoperative staging was T2-T4bN1-2 and/or M0-M1 or MX. Tumor-draining lymph nodes were harvested at intended cystectomy for the extraction of T lymphocytes. This was followed by expansion of the T lymphocytes in a cell culture, and subsequent reinfusion of these autologous tumor-specific T lymphocytes. Responses to therapy were evaluated by CT scans according to Response Evaluation Criteria In Solid Tumors (RECIST) and clinical follow-up, according to the research protocol.

RESULTS

Nine out of 18 patients were treated. Treatment was feasible and safe. In two out of nine immunologically treated patients, objective responses were detected in terms of diminished or obliterated nodal metastases. When excluding three patients with disseminated osseous metastases plus one with a T4b tumor left in situ, a success rate of two out of six treated patients was seen. The two responders had survival times of 35 and 11 months, respectively. No toxicity was recorded.

CONCLUSIONS

Infusion of expanded autologous tumor-specific T lymphocytes is feasible and safe, and objective responses according to RECIST were recorded. One objective responder to immunotherapy displayed notably long overall survival.

Immunotherapy of Metastatic Colorectal Cancer: Prevailing Challenges and New Perspectives

Patients with recurring or metastatic colorectal cancer (mCRC) have strikingly low long-term survival, while conventional treatments such as chemotherapeutic intervention and radiation therapy marginally improve longevity. Although, many factors involving immunosurveillance and immunosuppression were recently validated as important for patient prognosis and care, a multitude of experimental immunotherapies designed to combat unresectable mCRC have, in few cases, successfully mobilized antitumor immune cells against malignancies, nor conclusively or consistently granted protection, complete remission, and/or stable disease from immunotherapy - of which benefit less than 10% of those receiving therapy. After decades of progress, however, new insights into the mechanisms of immunosuppression, tolerance, and mutation profiling established novel therapies that circumvent these immunological barriers. This review underlines the most exciting methods to date that manipulate immune cells to curb mCRC, including adoptive cell therapy, dendritic cell vaccines, and checkpoint inhibitor antibodies - of which hint at effective and enduring protection against disease progression and undetected micrometastases.

Phase I/II study of adjuvant immunotherapy with sentinel lymph node T lymphocytes in patients with colorectal cancer

Although the development of multi-disciplinary management has improved the survival of colorectal cancer (CRC), the prognosis of metastatic CRC patients remains poor. Accumulating evidence has demonstrated that immunotherapy with cancer vaccines and adoptive T cell transfusions may improve outcomes as an adjuvant to current standard CRC treatment. In this phase I/II study, 71 CRC patients who underwent radical surgery (stage I-III, n = 46) or palliative surgery (stage IV with non-resectable synchronous metastases, n = 25) were included. In the first part of this study, sentinel lymph nodes (SLNs) were intraoperatively identified in 55 patients (46 with stage I-III CRC and 9 with stage IV CRC). SLN-T lymphocytes were expanded ex vivo for a median of 28.5 days (range 23-33 days). Thereafter, a median of 153 × 10(6) cells (range 20.7-639.0 × 10(6)) were transfused. No treatment-related toxicity was observed. In the second part of this study, the stage IV patients were routinely followed. The 24-month survival rate of the SLN-T lymphocyte group was significantly higher than that of the control group: 55.6 versus 17.5% (p = 0.02). The median overall survival of the SLN-T lymphocyte and control groups was 28 and 14 months, respectively. Our study showed that adjuvant SLN-T lymphocyte immunotherapy is feasible and safe for postoperative CRC patients. Additionally, this therapy may improve the long-term survival of metastatic CRC. Further investigation of the clinical efficacy and anti-tumor immunity is warranted.

Adoptive cellular therapy of cancer: exploring innate and adaptive cellular crosstalk to improve anti-tumor efficacy

ABSTRACT 

The mammalian immune system has evolved to produce multi-tiered responses consisting of both innate and adaptive immune cells collaborating to elicit a functional response to a pathogen or neoplasm. Immune cells possess a shared ancestry, suggestive of a degree of coevolution that has resulted in optimal functionality as an orchestrated and highly collaborative unit. Therefore, the development of therapeutic modalities that harness the immune system should consider the crosstalk between cells of the innate and adaptive immune systems in order to elicit the most effective response. In this review, the authors will discuss the success achieved using adoptive cellular therapy in the treatment of cancer, recent trends that focus on purified T cells, T cells with genetically modified T-cell receptors and T cells modified to express chimeric antigen receptors, as well as the use of unfractionated immune cell reprogramming to achieve optimal cellular crosstalk upon infusion for adoptive cellular therapy.

Multiplex B cell characterization in blood, lymph nodes, and tumors from patients with malignancies

B lymphocytes contribute to immune surveillance, by tumor-specific Abs and Ag presentation to T lymphocytes, but are insufficiently studied in humans. In this article, we report a flow cytometric investigation of B lymphocyte subpopulations in blood, lymph nodes (LNs), and malignant tissues from 20 patients operated on because of advanced solid tumors. The CD19(+) compartment in peripheral blood was essentially unaltered in patients, as compared with healthy control subjects. In metastatic LNs, signs of B lymphocyte activation were observed, as evidenced by increased proportions of plasmablasts and CD86-expressing cells. In tumor-infiltrating B lymphocytes (TIL-B), both switched memory cells and plasmablasts were expanded, as compared with nonmalignant epithelium. Moreover, pronounced skewing of Igλ/Igκ ratio was evident among TIL-Bs. By spectratype analysis on IgH, we confirmed a monoclonal expansion of the Vh7 family in TIL-B, also present in a tumor-associated LN. Sequencing the clonally expanded Vh7 revealed signs of somatic hypermutation. In conclusion, B lymphocytes in cancer patients exhibit signs of activation in tumor-associated tissues, likely induced by recognition of tumor Ags. Increased numbers of switched memory cells and plasmablasts in combination with clonal expansion and signs of somatic hypermutation suggest a CD4(+) T lymphocyte-dependent antitumoral response, which may be exploited for immunotherapy.

Immunotherapy for metastatic colorectal cancer: present status and new options

Although no immunotherapeutic treatment is approved for colorectal cancer (CRC) patients, promising results from clinical trials suggest that several immunotherapeutic strategies may prove efficacious and applicable to this group of patients. This review describes the immunogenicity of CRC and presents the most interesting strategies investigated so far: cancer vaccination including antigen-defined vaccination and dendritic cell vaccination, chemo-immunotherapy, and adoptive cell transfer. Future treatment options as well as the possibility of combining existing therapies will be discussed along with the challenges presented by tumor escape mechanisms.

Sentinel node detection in renal cell carcinoma. A feasibility study for detection of tumour-draining lymph nodes

OBJECTIVE

To evaluate the feasibility of performing sentinel node detection in patients with renal cell carcinoma (RCC).

MATERIALS AND METHODS

An open series of 13 arbitrarily selected patients with T1b-T3b RCC scheduled for radical nephrectomy at a single Tertiary Academic Centre were examined with different modalities of sentinel node detection. Preoperative ultrasonography-guided injection of radioactive isotope, lymphoscintigram and single photon emission computed tomography/computed tomography, followed by intraoperative gamma-probe detection and Patent Blue detection, as well as postoperative scintigram of the main specimen were the planned interventions. These investigations were performed in conjunction with intended open radical nephrectomy.

RESULTS

In 10 of the 13 patients sentinel node detection was achieved with 32 sentinel nodes displayed. Radio-guided surgery using an intraoperative gamma-probe resulted in the highest realtive detection rate with detection of sentinel nodes in nine patients. In total, nine metastatic sentinel nodes were detected in three patients. One patient, preoperatively staged as N+, was restaged after sentinel node detection and histopathology as pN0.

CONCLUSIONS

Sentinel node detection in renal tumours is feasible although evaluation of different modes of detection needs further refinement and standardization. All nodes preoperatively detected by routine computed tomography as suspicious metastatic lesions were confirmed as sentinel nodes, including two nodes considered as metastatic by preoperative routine imaging but ultimately staged as non-metastatic sentinel nodes.

Evidence for immunosurveillance in intestinal premalignant lesions

The immunosurveillance theory argues that the immune system recognizes tumour-specific antigens expressed by transformed cells, which results in the destruction of cancer precursors before they become clinically manifest. As a model for the development of cancer, we set out to study premalignant lesions and immune responses in sentinel lymph nodes from patients with long-standing ulcerative colitis and progression of mucosal dysplasia. Mesenteric lymph nodes draining dysplastic and normal intestinal segments were identified by sentinel node technique during surgery in 13 patients with ulcerative colitis who were subjected to colectomy because of intestinal dysplasia. T cells were extracted from the lymph nodes and analysed by flow cytometry, and lymphocyte proliferation assays were set up in the presence of extracts from dysplastic and normal intestinal mucosa. Increase in CD4/CD8 ratio was observed in sentinel lymph nodes draining dysplastic epithelium compared to normal mucosa. The increase in CD4(+) T cells in relation to CD8(+) T cells correlated with the degree of dysplasia reflected by a significant increase in the ratio against low-grade dysplasia compared to indefinite dysplastic lesions. The T-cell response was specific to antigens from dysplastic epithelial lining as seen in proliferation assays. The observation suggests an important surveillance role for the immune system against premalignant intestinal lesions in patients with long-standing ulcerative colitis.

Pilot study of sentinel-node-based adoptive immunotherapy in advanced colorectal cancer

Background

Despite optimal surgical treatment and modern adjuvant therapies, 50% of patients diagnosed with colorectal cancer die within 5 years. Immunotherapy offers an appealing complement to traditional chemotherapy, with possible long-term protection against tumor recurrences through immunological memory. We have conducted a pilot study of a novel adoptive immunotherapy, using autologous, in vitro expanded lymphocytes isolated from the tumor-draining sentinel lymph node.

Study Design

Sentinel nodes were recovered from 16 patients with disseminated or locally advanced, high-risk colorectal cancer. Single-cell suspensions of sentinel-node-acquired lymphocytes were clonally expanded in vitro in the presence of autologous tumor extract and returned as a transfusion. Patients were followed with clinical and radiological evaluations. Long-term survival was compared with traditionally treated controls.

Results

Sentinel-node-acquired CD4⁺ Th1-lymphocytes could be clonally expanded in vitro and safely administered to all 16 patients without side-effects. In four out of nine stage IV patients, complete tumor regression occurred. Median survival time in the stage IV patients (n = 9) was 2.6 years, as compared with 0.8 years in conventionally treated controls. A dose-dependent effect with regards to reduced tumor burden and long-term survival was observed.

Conclusion

Sentinel-node-based adoptive immunotherapy is feasible; the method has shown no apparent side-effects and appears to convey therapeutic antitumor effects. Further studies are justified to determine its efficacy and precise role in the treatment of colorectal cancer.

At the crossroads of T helper lineage commitment-Epigenetics points the way

The immune system has the capacity to respond to various types of pathogens including bacteria, viruses, tumors and parasites. This requires a flexible immune system, which in part depends on the development of alternative effector T helper cells, with different cytokine repertoires that direct the overall immune response. The reciprocal effects of the T helper subtypes Th1 and Th2 are well documented, but the mechanisms involved in alternative cytokine expression and silencing are less well defined. Introduction of advances within the field of chromatin folding and epigenetic regulation of transcription has begun to explain some of the fundamental principles of T helper cell development. In addition, epigenetic regulation has proven essential also for the more recently discovered T helper cell subtypes; regulatory T cells and the Th17 lineage. As the importance of proper epigenetic regulation becomes evident, attention is also focused on the potential harmfulness of epigenetic dysregulation. Autoimmunity and allergy are two clinical situations that have been implicated as results of imperfect cytokine silencing. This review will address recent advances in the field of epigenetic regulation of T lymphocytes and their maturation from naive cells into different effector T cell lineages. In particular, epigenetic involvement in regulation of key effector cytokines and specific transcription factors determining the CD4(+) T lymphocyte lineage commitment will be discussed.

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F. Pagès, A. Berger, F. Zinzindohoué, A. Kirilovsky, J. Galon, W.-H. Fridman Lymph node dissection is an integral part of the surgical resection of colon cancers; it completes the wide regional resection of tumor and it allows prognostic evaluation through accurate staging. Studies have demonstrated an immune reaction to the tumoral site which attests to an ongoing dialog between the tumor and systemic defenses. The regional lymph nodes constitute an important first line of immune defense where initial host response is initiated or, inversely, they may participate in a local state of immunosuppression. This article reviews current knowledge on intra-tumoral and nodal immune status in colorectal cancers and attempts to evaluate the potential immunologic implications of lymph node dissection.

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F. Pagès, A. Berger, F. Zinzindohoué, A. Kirilovsky, J. Galon, W.-H. Fridman Lymph node dissection is an integral part of the surgical resection of colon cancers; it completes the wide regional resection of tumor and it allows prognostic evaluation through accurate staging. Studies have demonstrated an immune reaction to the tumoral site which attests to an ongoing dialog between the tumor and systemic defenses. The regional lymph nodes constitute an important first line of immune defense where initial host response is initiated or, inversely, they may participate in a local state of immunosuppression. This article reviews current knowledge on intra-tumoral and nodal immune status in colorectal cancers and attempts to evaluate the potential immunologic implications of lymph node dissection.

CpG methylation of the IFNG gene as a mechanism to induce immunosuppression [correction of immunosupression] in tumor-infiltrating lymphocytes

The execution of appropriate gene expression patterns during immune responses is of eminent importance where CpG methylation has emerged as an essential mechanism for gene silencing. We have charted the methylation status of regulatory elements in the human IFNG gene encoding the signature cytokine of the Th1 response. Surprisingly, human naive CD4(+) T lymphocytes displayed hypermethylation at the IFNG promoter region, which is in sharp contrast to the completely demethylated status of this region in mice. Th1 differentiation induced demethylation of the IFNG promoter and the upstream conserved nucleotide sequence 1 enhancer region, whereas Th2-differentiated lymphocytes remained hypermethylated. Furthermore, CD19(+) B lymphocytes displayed hypomethylation at the IFNG promoter region with a similar pattern to Th1 effector cells. When investigating the methylation status among tumor-infiltrating CD4(+) T lymphocytes from patients with colon cancer, we found that tumor-infiltrating lymphocytes cells are inappropriately hypermethylated, and thus not confined to the Th1 lineage. In contrast, CD4(+) T cells from the tumor draining lymph node were significantly more demethylated than tumor-infiltrating lymphocytes. We conclude that there are obvious interspecies differences in the methylation status of the IFNG gene in naive CD4(+) T lymphocytes, where Th1 commitment in human lymphocytes involves demethylation before IFNG expression. Finally, investigations of tumor-infiltrating lymphocytes and CD4(+) cells from tumor draining lymph node demonstrate methylation of regulatory regions within key effector genes as an epigenetic mechanism of tumor-induced immunosuppression.

Metinel node--the first lymph node draining a metastasis--contains tumor-reactive lymphocytes

Background

We previously identified tumor-reactive lymphocytes in the first lymph nodes that drain the primary tumor. In this study, we performed lymphatic mapping to investigate the possibility of finding the first lymph nodes that drain metastases, and of learning whether these lymph nodes contained tumor-reactive lymphocytes suitable for adoptive immunotherapy.

Methods

Nineteen patients were studied. The primary tumor site was colorectal cancer in seven patients, malignant melanoma in four, ovarian cancer and breast cancer in two, and one each with pancreatic cancer, cholangiocarcinoma, leiomyosarcoma, and squamous cellular cancer of the tongue. By injection of Patent blue dye or radioactive tracers around the metastases, we identified draining lymph nodes from liver metastases (n = 9), intra-abdominal local recurrences (n = 3), and regional lymph node metastases (n = 7). In six patients, a preoperative lymphoscintigraphy was performed.

Results

We located the first draining lymph node or nodes from metastases or local recurrences; we named them “metinel nodes.” Lymphocytes from the metinel nodes proliferated, showed clonal expansion, and produced interferon gamma (via in vitro expansions on stimulation with tumor homogenate) and interleukins, all of which demonstrate the characteristics of tumor-reactive lymphocytes. Eight of the nineteen patients received immunotherapy on the basis of tumor-reactive T cells derived from the metinel nodes.

Conclusions

We demonstrate that it is possible to locate the first lymph nodes draining subcutaneous, lymphatic, and visceral metastases, the so-called metinel nodes. Metinel node–derived lymphocytes may be used to treat disseminated solid cancer, and clinical trials should evaluate the effect of such treatment.

Immunobiology of the sentinel lymph node and its potential role for antitumour immunity

The sentinel lymph node (SLN) is thought to be an important lymphoid organ for protecting against metastasis and is thought to play a crucial part in provoking antitumour immunity. Because SLN biopsy is undertaken for various types of cancers, such as malignant melanoma and breast cancer, SLN mapping has become a standard procedure, thereby eliminating unnecessary lymph-node resection in patients who do not have affected nodes. The immune surveillance activities of the SLN in melanoma and breast cancer are thought to be suppressed, whereas in cancers of gastrointestinal-tract, the presence of T cells in the SLN has not been shown to suppress the host's immune function. Furthermore, cell death after primary systemic chemotherapy for solid tumours can provoke an antigen-specific immunity in the tumour, which affects tumour response to treatment and, therefore, survival in patients. This review discusses the immunobiology of the SLN and potential strategies for activation of antitumour immunity by primary systemic chemotherapy and other modalities, in terms of tumour-size reduction and survival benefit.