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

Research advances on TIL therapy for colorectal cancer

Colorectal cancer (CRC) is a prevalent gastrointestinal malignancy. Tumor-infiltrating lymphocyte (TIL) therapy, a form of adoptive cellular therapy (ACT), involves isolating T lymphocytes from tumor tissues, in vitro expansion, and reintroduction into the body to target and eliminate tumor cells. This article presents an overview of the development and application of TIL therapy in CRC, as well as the associated challenges.

Generation of colon cancer-derived tumor-infiltrating T cells (TILs) for adoptive cell therapy

Adoptive cell therapy (ACT) using specific immune cells and stem cells has emerged as a promising treatment option that could complement traditional cancer therapies in the future. In particular, tumor-infiltrating lymphocytes (TILs) have been shown to be effective against solid tumors in various clinical trials. Despite the enormous disease burden and large number of premature deaths caused by colorectal cancer (CRC), studies on TILs isolated from tumor tissue of patients with CRC are still rare. To date, studies on ACT often lack controlled and comparable expansion processes as well as selected ACT-relevant T-cell populations. We describe a procedure for generating patient-specific TILs, which are prerequisites for clinical trials of ACT in CRC. The manufacturing and characteristics of these TILs differ in important modalities from TILs commonly used for this therapeutic approach. Tumor tissue samples were obtained from 12 patients undergoing surgery for primary CRC, predominantly with low microsatellite instability (pMMR-MSI-L). Tumors in the resected specimens were examined pathologically, and an approved volume of tumor tissue was transferred to a disposable perfusion bioreactor. Tissue samples were subjected to an automatically controlled and highly reproducible cultivation process in a GMP-conform, closed perfusion bioreactor system using starting medium containing interleukin-2 and interleukin-12. Outgrowth of TIL from tissue samples was initiated by short-term supplementation with a specific activation cocktail. During subsequent expansion, TILs were grown in interleukin-2-enriched medium. Expansion of TILs in a low-scaled, two-phase process in the Zellwerk ZRP bioreactor under hyperoxic conditions resulted in a number of approximately 2 × 10⁹ cells. The expanded TILs consisted mainly (73%) of the ACT-relevant CD3⁺/CD8⁺ effector memory phenotype (CD45RO⁺/CCR7^-). TILs harvested under these conditions exhibited high functional potential, which was confirmed upon nonspecific stimulation (interferon-γ, tumor necrosis factor-α cytokine assay).

Tumor-infiltrating lymphocytes for treatment of solid tumors: It takes two to tango?

Tumor-infiltrating lymphocytes (TILs), frontline soldiers of the adaptive immune system, are recruited into the tumor site to fight against tumors. However, their small number and reduced activity limit their ability to overcome the tumor. Enhancement of TILs number and activity against tumors has been of interest for a long time. A lack of knowledge about the tumor microenvironment (TME) has limited success in primary TIL therapies. Although the advent of engineered T cells has revolutionized the immunotherapy methods of hematologic cancers, the heterogeneity of solid tumors warrants the application of TILs with a wide range of specificity. Recent advances in understanding TME, immune exhaustion, and immune checkpoints have paved the way for TIL therapy regimens. Nowadays, TIL therapy has regained attention as a safe personalized immunotherapy, and currently, several clinical trials are evaluating the efficacy of TIL therapy in patients who have failed conventional immunotherapies. Gaining favorable outcomes following TIL therapy of patients with metastatic melanoma, cervical cancer, ovarian cancer, and breast cancer has raised hope in patients with refractory solid tumors, too. Nevertheless, TIL therapy procedures face several challenges, such as high cost, timely expansion, and technical challenges in selecting and activating the cells. Herein, we reviewed the recent advances in the TIL therapy of solid tumors and discussed the challenges and perspectives.

Comprehensive analysis of the immune implication of FABP4 in colon adenocarcinoma

Background

Fatty acid-binding protein 4 (FABP4) has been reported to be associated with tumor progress and poor prognosis in various cancers. However, the relationship between FABP4 expression and tumor immunity in colon adenocarcinoma (COAD) is still poorly understood.

Methods

FABP4 mRNA expression was analyzed using The Cancer Genome Atlas (TCGA)-COAD data. FABP4 protein staining was performed by immunohistochemistry (IHC) staining in our 10 paired COAD samples and corresponding adjacent noncancerous tissues. The association between FABP4 and immune cell infiltration was evaluated by Tumor Immune Estimation Resource (TIMER) database. FABP4 coexpressed genes were identified based on Cancer Cell Line Encyclopedia (CCLE) database, which were employed for further enrichment analysis. FABP4 related immunomodulators was identified by Tumor and Immune System Interaction Database (TISIDB) database, and a prognostic risk signature was constructed based on FABP4-related immunomodulators using stepwise Cox regression analysis. A nomogram consists of FABP4 related immunomodulators signature and clinical parameters was developed to predict the overall survival (OS).

Results

In TCGA data, we found that the decreased FABP4 mRNA expression in COAD samples compared with normal samples, and low FABP4 mRNA expression was associated with B cells, CD4+ T cells, CD8+ T cells, myeloid dendritic cells, macrophages, and neutrophils. In our 10 paired samples, the protein levels of COAD were lower in all COAD tissues than in their adjacent noncancerous tissues. Functional enrichment analysis revealed that FABP4 coexpressed genes were mostly enriched in immune-related pathways. Based on 54 FABP4-related immunomodulators, a 2-gene FABP4-related prognostic risk signature was developed, and the signature stratified the patients into the high-risk and low-risk groups with statistically different survival outcomes. The Nomogram consists of the prognostic signature and clinical parameters had a certain predictability for prognosis of COAD patients.

Conclusion

These findings suggest that FABP4 is associated with 2-gene immune signature which also correlate with the prognosis of COAD patients.

Adoptive T-Cell Therapy in Advanced Colorectal Cancer: A Systematic Review

Colorectal cancer (CRC) is the second leading cause of cancer-related deaths in the US. For the vast majority of patients with advanced CRC (ie, for those in whom metastatic tumors are unresectable), treatment is palliative and typically involves chemotherapy, biologic therapy, and/or immune checkpoint inhibition. In recent years, the use of adoptive T-cell therapy (ACT), leveraging the body’s own immune system to recognize and target cancer, has become increasingly popular. Unfortunately, while ACT has been successful in the treatment of hematological malignancies, it is less efficacious in advanced CRC due in part to a lack of productive immune infiltrate. This systematic review was conducted to summarize the current data for the efficacy and safety of ACT in advanced CRC. We report that ACT is well tolerated in patients with advanced CRC. Favorable survival estimates among patients with advanced CRC receiving ACT demonstrate promise for this novel treatment paradigm. However, additional stage I/II clinical trials are needed to establish the efficacy and safety of ACT in patients with CRC.

The Role of the Tumor Microenvironment and Treatment Strategies in Colorectal Cancer

Colorectal cancer (CRC) has the second highest mortality rate among all cancers worldwide. Surgery, chemotherapy, radiotherapy, molecular targeting and other treatment methods have significantly prolonged the survival of patients with CRC. Recently, the emergence of tumor immunotherapy represented by immune checkpoint inhibitors (ICIs) has brought new immunotherapy options for the treatment of advanced CRC. As the efficacy of ICIs is closely related to the tumor immune microenvironment (TME), it is necessary to clarify the relationship between the immune microenvironment of CRC and the efficacy of immunotherapy to ensure that the appropriate drugs are selected. We herein review the latest research progress in the immune microenvironment and strategies related to immunotherapy for CRC. We hope that this review helps in the selection of appropriate treatment strategies for CRC patients.

Personalized Immunotherapy in Colorectal Cancers: Where Do We Stand?

Colorectal cancer (CRC) is the second leading cause of cancer death in the world. Immunotherapy using monoclonal antibodies, immune-checkpoint inhibitors, adoptive cell therapy, and cancer vaccines has raised great hopes for treating poor prognosis metastatic CRCs that are resistant to the conventional therapies. However, high inter-tumor and intra-tumor heterogeneity hinder the success of immunotherapy in CRC. Patients with a similar tumor phenotype respond differently to the same immunotherapy regimen. Mutation-based classification, molecular subtyping, and immunoscoring of CRCs facilitated the multi-aspect grouping of CRC patients and improved immunotherapy. Personalized immunotherapy using tumor-specific neoantigens provides the opportunity to consider each patient as an independent group deserving of individualized immunotherapy. In the recent decade, the development of sequencing and multi-omics techniques has helped us classify patients more precisely. The expansion of such advanced techniques along with the neoantigen-based immunotherapy could herald a new era in treating heterogeneous tumors such as CRC. In this review article, we provided the latest findings in immunotherapy of CRC. We elaborated on the heterogeneity of CRC patients as a bottleneck of CRC immunotherapy and reviewed the latest advances in personalized immunotherapy to overcome CRC heterogeneity.

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.

Promising New Tools for Targeting p53 Mutant Cancers: Humoral and Cell-Based Immunotherapies

Transcription factor and oncosuppressor protein p53 is considered as one of the most promising molecular targets that remains a high-hanging fruit in cancer therapy. TP53 gene encoding the p53 protein is known to be the most frequently mutated gene in human cancers. The loss of transcriptional functions caused by mutations in p53 protein leads to deactivation of intrinsic tumor suppressive responses associated with wild-type (WT) p53 and acquisition of new pro-oncogenic properties such as enhanced cell proliferation, metastasis and chemoresistance. Hotspot mutations of p53 are often immunogenic and elicit intratumoral T cell responses to mutant p53 neoantigens, thus suggesting this protein as an attractive candidate for targeted anti-cancer immunotherapies. In this review we discuss the possible use of p53 antigens as molecular targets in immunotherapy, including the application of T cell receptor mimic (TCRm) monoclonal antibodies (mAbs) as a novel powerful approach.

Immune Characters and Plasticity of the Sentinel Lymph Node in Colorectal Cancer Patients

Purpose

This study is aimed at immunologically characterizing sentinel lymph nodes (SNs) in colorectal cancer (CRC) patients and identifying changes in immunological phenotype and function of SNs isolated from the tumor immunosuppressive microenvironment.

Methods

A total of 53 pairs of matched SNs and non-SNs (NSNs) were collected by using a lymph node tracer dye. Flow cytometry was performed to detect the immunophenotype of T cells as well as the expression of activation and inhibitory markers. Differential expression and distribution of characteristic immune cell markers were analyzed by multiplex immunohistochemistry (mIHC). Transcriptomics analysis was conducted to compare the differences in the expression of immune-related genes among lymph nodes. The ex vivo culture of lymph nodes was carried out to examine changes in immunological phenotypes and functions.

Results

Compared with NSNs, SNs harbored a significantly higher percentage of regulatory T cells (Tregs) but a lower proportion of MoMDSCs. As indicated in the mIHC assays, Tregs, T follicular helper (Tfh) cells, and M2 macrophages were mainly distributed in cortical areas, germinal centers, and subcapsular sinus areas, respectively, while significantly higher numbers of Tregs and Tfh cells were detected in SNs as compared to NSNs. Moreover, GSEA revealed that T cell activation genes and CD8+ T cell exhaustion-related genes are enriched in SNs and NSNs, respectively. The ex vivo culture led to an increase in the proportion of CD4+ cells, while activating T cells in SNs. In addition, SNs displayed a higher increase in the expression of cytokines IFN-γ, TNF-α, and sFas than NSNs.

Conclusion

SNs are shown to be in an immune active state in vivo, while highly expressing inhibitory cytokines and suppressive markers. The ex vivo culture enhanced antitumor immunological function of SN-T cells, providing a starting material for adoptive cell therapy for CRC.

Adoptive Immunotherapy beyond CAR T-Cells

Adoptive cell immunotherapy (ACT) is a vibrant field of cancer treatment that began progressive development in the 1980s. One of the most prominent and promising examples is chimeric antigen receptor (CAR) T-cell immunotherapy for the treatment of B-cell hematologic malignancies. Despite success in the treatment of B-cell lymphomas and leukemia, CAR T-cell therapy remains mostly ineffective for solid tumors. This is due to several reasons, such as the heterogeneity of the cellular composition in solid tumors, the need for directed migration and penetration of CAR T-cells against the pressure gradient in the tumor stroma, and the immunosuppressive microenvironment. To substantially improve the clinical efficacy of ACT against solid tumors, researchers might need to look closer into recent developments in the other branches of adoptive immunotherapy, both traditional and innovative. In this review, we describe the variety of adoptive cell therapies beyond CAR T-cell technology, i.e., exploitation of alternative cell sources with a high therapeutic potential against solid tumors (e.g., CAR M-cells) or aiming to be universal allogeneic (e.g., CAR NK-cells, γδ T-cells), tumor-infiltrating lymphocytes (TILs), and transgenic T-cell receptor (TCR) T-cell immunotherapies. In addition, we discuss the strategies for selection and validation of neoantigens to achieve efficiency and safety. We provide an overview of non-conventional TCRs and CARs, and address the problem of mispairing between the cognate and transgenic TCRs. Finally, we summarize existing and emerging approaches for manufacturing of the therapeutic cell products in traditional, semi-automated and fully automated Point-of-Care (PoC) systems.

Chemotherapy but Not the Tumor Draining Lymph Nodes Determine the Immunotherapy Response in Secondary Tumors

Immunotherapies are used as adjuvant therapies for cancers. However, knowledge of how traditional cancer treatments affect immunotherapies is limited. Using mouse models, we demonstrate that tumor-draining lymph nodes (TdLNs) are critical for tumor antigen-specific T cell response. However, removing TdLNs concurrently with established primary tumors did not affect the immune checkpoint blockade (ICB) response on localized secondary tumor due to immunotolerance in TdLNs and distribution of antigen-specific T cells in peripheral lymphatic organs. Notably, treatment response improved with sequential administration of 5-fluorouracil (5-FU) and ICB compared with concurrent administration of ICB with 5-FU. Immune profiling revealed that using 5-FU as induction treatment increased tumor visibility to immune cells, decreased immunosuppressive cells in the tumor microenvironment, and limited chemotherapy-induced T cell depletion. We show that the effect of traditional cytotoxic treatment, not TdLNs, influences immunotherapy response in localized secondary tumors. We postulate essential considerations for successful immunotherapy strategies in clinical conditions.

Relationships Between Immune Landscapes, Genetic Subtypes and Responses to Immunotherapy in Colorectal Cancer

Colorectal cancer (CRC) is highly heterogeneous at the genetic and molecular level, which has major repercussions on the efficacy of immunotherapy. A small subset of CRCs exhibit microsatellite instability (MSI), a molecular indicator of defective DNA mismatch repair (MMR), but the majority are microsatellite-stable (MSS). The high tumor mutational burden (TMB) and neoantigen load in MSI tumors favors the infiltration of immune effector cells, and antitumor immune responses within these tumors are strong relative to their MSS counterparts. MSI has emerged as a major predictive marker for the efficacy of immune checkpoint blockade over the last few years and nivolumab or pembrolizumab targeting PD-1 has been approved for patients with MSI refractory or metastatic CRC. However, some MSS tumors show DNA polymerase epsilon (POLE) mutations that also confer a very high TMB and may also be heavily infiltrated by immune cells making them amenable to respond to immune checkpoint inhibitors (ICI). In this review we discuss the role of the different immune landscapes in CRC and their relationships with defined CRC genetic subtypes. We discuss potential reasons why immune checkpoint blockade has met with limited success for the majority of CRC patients, despite the finding that immune cell infiltration of primary non-metastatic tumors is a strong predictive, and prognostic factor for relapse and survival. We then consider in which ways CRC cells develop mechanisms to resist ICI. Finally, we address the latest advances in CRC vaccination and how a personalized neoantigen vaccine strategy might overcome the resistance of MSI and MSS tumors in patients for whom immune checkpoint blockade is not a treatment option.

Atypical Memory and Regulatory B Cell Subsets in Tumor Draining Lymph Nodes of Head and Neck Squamous Cell Carcinoma Correlate with Good Prognostic Factors

Research on the role of B cells in the development and modulation of antitumor immunity has increased in recent years; however, knowledge about B cell phenotype and function in tumor draining lymph nodes (TDLNs) is still incomplete. This study aimed to investigate changes in the phenotypic profile of B cells in TDLNs of head and neck squamous cell carcinoma (HNSCC) during disease progression. Mononuclear cells were isolated from TDLNs and stained with antibodies for CD19 and other B cell-related markers and analyzed by flow cytometry. CD19⁺ B cells comprised 38.6 ± 8.9% of lymphocytes in TDLNs of HNSCC. Comparison of metastatic and non-metastatic LNs disclosed no significant differences in the frequencies of B cell subsets including antigen-experienced, naïve, switched, unswitched, atypical memory, marginal zone-like B cells, and B cells with regulatory phenotypes. The percentage of atypical memory (CD27^-IgM^-IgD^-) B cells was significantly higher in patients with tongue SCC with no involved LNs (p = 0.033) and correlated inversely with the number of involved LNs. The frequency of CD24^hiCD38^hi B cells was significantly higher in non-metastatic LNs of patients with grade I compared to grade II (p = 0.016), and the percentage of CD5⁺ B cells decreased as tumors progressed from stage III to IV (p = 0.008). Our data show that in TDLNs of HNSCC, the frequency of B cells with atypical memory and regulatory phenotypes was significantly associated with good prognostic factors; however, their function remains to be investigated.

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.

Facing the future: challenges and opportunities in adoptive T cell therapy in cancer

INTRODUCTION

In recent years, immunotherapy for the treatment of solid cancer has emerged as a promising therapeutic alternative. Adoptive cell therapy (ACT), especially T cell-based, has been found to cause tumor regression and even cure in a percentage of treated patients. Checkpoint inhibitors further underscore the potential of the T cell compartment in the treatment of cancer. Not all patients respond to these treatments; however, many challenges remain.

AREAS COVERED

This review covers the challenges and progress in tumor antigen target identification and selection, and cell product manufacturing for T cell ACT. Tumor immune escape mechanisms and strategies to overcome those in the context of T cell ACT are also discussed.

EXPERT OPINION

The immunotherapy toolbox is rapidly expanding and improving, and the future promises further breakthroughs in the T cell ACT field. The heterogeneity of the tumor microenvironment and the multiplicity of tumor immune escape mechanisms pose formidable challenges to successful T cell immunotherapy in solid tumors, however. Individualized approaches and strategies combining treatments targeting different immunotherapeutic aspects will be needed in order to expand the applicability and improve the response rates in future.

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.

Trial Watch: Adoptively transferred cells for anticancer immunotherapy

Immunotherapies aimed at strengthening immune effector responses against malignant cells are growing at exponential rates. Alongside, the impressive benefits obtained by patients with advanced melanoma who received adoptively transferred tumor-infiltrating lymphocytes (TILs) have encouraged the scientific community to pursue adoptive cell transfer (ACT)-based immunotherapy. ACT involves autologous or allogenic effector lymphocytes that are generally obtained from the peripheral blood or resected tumors, expanded and activated ex vivo, and administered to lymphodepleted patients. ACT may be optionally associated with chemo- and/or immunotherapeutics, with the overall aim of enhancing the proliferation, persistence and functionality of infused cells, as well as to ensure their evolution in an immunological permissive local and systemic microenvironment. In addition, isolated lymphocytes can be genetically engineered to endow them with the ability to target a specific tumor-associated antigen (TAA), to increase their lifespan, and/or to reduce their potential toxicity. The infusion of chimeric antigen receptor (CAR)-expressing cytotoxic T lymphocytes redirected against CD19 has shown promising clinical efficacy in patients with B-cell malignancies. Accordingly, the US Food and Drug Administration (FDA) has recently granted 'breakthrough therapy' designation to a CAR-based T-cell therapy (CTL019) for patients with B-cell malignancies. Considerable efforts are now being devoted to the development of efficient ACT-based immunotherapies for non-hematological neoplasms. In this Trial Watch, we summarize recent clinical advances on the use of ACT for oncological indications.

Immunotherapy in gastrointestinal cancers

Gastrointestinal (GI) cancers such as gastric, esophageal, pancreas, hepatobiliary, colorectal and anal cancers are a major cause of cancer related mortality worldwide. Traditional treatment options such as chemotherapy, surgery, radiation therapy, monoclonal antibodies and anti-angiogenic agents have been the backbone of treatment of GI cancers in various stages. Current cancer research is moving forward to incorporate immunotherapies in the treatment of GI cancers either as single agent or in combination with current available treatment modalities. This review summarizes the existing and ongoing immunotherapies in the treatment of GI cancers.

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.

Potential use of lymph node-derived HPV-specific T cells for adoptive cell therapy of cervical cancer

Adoptive transfer of tumor-specific T cells, expanded from tumor-infiltrating lymphocytes or from peripheral blood, is a promising immunotherapeutic approach for the treatment of cancer. Here, we studied whether the tumor-draining lymph nodes (TDLN) of patients with human papillomavirus (HPV)-induced cervical cancer can be used as a source for ACT. The objectives were to isolate lymph node mononuclear cells (LNMC) from TDLN and optimally expand HPV-specific CD4+ and CD8+ T cells under clinical grade conditions. TDLN were isolated from 11 patients with early-stage cervical cancer during radical surgery. Isolated lymphocytes were expanded in the presence of HPV16 E6 and E7 clinical grade synthetic long peptides and IL-2 for 22 days and then analyzed for HPV16 specificity by proliferation assay, multiparameter flow cytometry and cytokine analysis as well as for CD25 and FoxP3 expression. Stimulation of LNMC resulted in expansion of polyclonal HPV-specific T cells in all patients. On average a 36-fold expansion of a CD4+ and/or CD8+ HPV16-specific T cell population was observed, which maintained its capacity for secondary expansion. The T helper type 1 cytokine IFNγ was produced in all cell cultures and in some cases also the Th2 cytokines IL-10 and IL-5. The procedure was highly reproducible, as evidenced by complete repeats of the stimulation procedures under research and under full good manufacturing practice conditions. In conclusion, TDLN represent a rich source of polyclonal HPV16 E6- and E7-specific T cells, which can be expanded under clinical grade conditions for adoptive immunotherapy in patients with cervical cancer.

Current Status and Perspective of Immunotherapy in Gastrointestinal Cancers

Cancer immunotherapy is at dawn of the Renaissance after the Medieval Dark Ages. Recent advances of understanding tumor immunology and molecular drug development are leading us to the epoch of cancer immunotherapy. Some types of immunotherapy have shown to provide survival benefit for patients with solid tumors such as malignant melanoma, renal cell carcinoma, or non-small cell lung cancer. Several studies have suggested that immune checkpoint inhibition might be effective in some patients with gastrointestinal cancers. However, the era of cancer immunotherapy in gastrointestinal cancers is still in an inchoate stage. Here we briefly review the current status and perspective of immunotherapeutic approaches in patients with gastrointestinal cancers.

Cell-based Immunotherapy for Colorectal Cancer with Cytokine-induced Killer Cells

Colorectal cancer is the third leading cancer worldwide. Although incidence and mortality of colorectal cancer are gradually decreasing in the US, patients with metastatic colorectal cancer have poor prognosis with an estimated 5-year survival rate of less than 10%. Over the past decade, advances in combination chemotherapy regimens for colorectal cancer have led to significant improvement in progression-free and overall survival. However, patients with metastatic disease gain little clinical benefit from conventional therapy, which is associated with grade 3~4 toxicity with negative effects on quality of life. In previous clinical studies, cell-based immunotherapy using dendritic cell vaccines and sentinel lymph node T cell therapy showed promising therapeutic results for metastatic colorectal cancer. In our preclinical and previous clinical studies, cytokine-induced killer (CIK) cells treatment for colorectal cancer showed favorable responses without toxicities. Here, we review current treatment options for colorectal cancer and summarize available clinical studies utilizing cell-based immunotherapy. Based on these studies, we recommend the use CIK cell therapy as a promising therapeutic strategy for patients with metastatic colorectal cancer.

Immune cell interplay in colorectal cancer prognosis

The immune response to colorectal cancer has proven to be a reliable measure of patient outcome in several studies. However, the complexity of the immune response in this disease is not well understood, particularly the interactions between tumour-associated cells and cells of the innate and adaptive immune system. This review will discuss the relationship between cancer associated fibroblasts and macrophages, as well as between macrophages and T cells, and demonstrate how each population may support or prevent tumour growth in a different immune environment.

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.

CEA/CD3-bispecific T cell-engaging (BiTE) antibody-mediated T lymphocyte cytotoxicity maximized by inhibition of both PD1 and PD-L1

Bispecific T cell-engaging (BiTE) antibodies recruit polyclonal cytotoxic T cells (CTL) to tumors. One such antibody is carcinoembryonic antigen (CEA) BiTE that mediates T cell/tumor interaction by simultaneously binding CD3 expressed by T cells and CEA expressed by tumor cells. A widely operative mechanism for mitigating cytotoxic T cell-mediated killing is the interaction of tumor-expressed PD-L1 with T cell-expressed PD-1, which may be partly reversed by PD-1/PD-L1 blockade. We hypothesized that PD-1/PD-L1 blockade during BiTE-mediated T cell killing would enhance CTL function. Here, we determined the effects of PD-1 and PD-L1 blockade during initial T cell-mediated killing of CEA-expressing human tumor cell lines in vitro, as well as subsequent T cell-mediated killing by T lymphocytes that had participated in tumor cell killing. We observed a rapid upregulation of PD-1 expression and diminished cytolytic function of T cells after they had engaged in CEA BiTE-mediated killing of tumors. T cell cytolytic activity in vitro could be maximized by administration of anti-PD-1 or anti-PD-L1 antibodies alone or in combination if applied prior to a round of T cell killing, but T cell inhibition could not be fully reversed by this blockade once the T cells had killed tumor. In conclusion, our findings demonstrate that dual blockade of PD-1 and PD-L1 maximizes T cell killing of tumor directed by CEA BiTE in vitro, is more effective if applied early, and provides a rationale for clinical use.

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.

Immune-based therapies in pancreatic and colorectal cancers and biomarkers of responsiveness

Immune-based strategies are the most promising treatments to improve cancer disease control. Early clinical trials are ongoing to test the safety and feasibility of immune-based therapies for gastrointestinal cancers. However, to date, immunotherapy has been only an experimental option for these diseases and a better understanding of their molecular, cellular, structural and clinical dissimilarities is crucial in the generation of tailored immunotherapeutic treatments. In this review, we will summarize the key mechanisms that regulate the action of immune system in cancer and the different immune-based approaches aimed at improving disease control in patients with advanced disease. We will then move on to discussing the current immunotherapeutic approaches in two types of gastrointestinal (colo-rectal and pancreatic) cancers, whose immune microenvironment has been lately object of intense analyses and has emerged as an important determinant of clinical outcome.

Cytokine-induced killer cells in the treatment of patients with renal cell carcinoma: a pooled meta-analysis

Cytokine-induced killer cells (CIKs) have been applied in multifarious cancer. Here, we address the connection between immune therapy and clinical responses by a systematic meta-analysis. A total of 385 patients (including 183 controls) were identified for renal cell cancer (RCC) in the seven selected trials. The estimated pooled complete response and partial response showed a significant improvement for patients receiving CIK immunotherapy compared with non-CIK therapy (p < 0.0001), which was up to 62% of clinical response. The overall analysis showed a significant survival benefit (1-year overall survival [OS]: p = 0.0002; 3-year OS: p < 0.0001) in favor of CIK-based therapy in RCC, thus a statistically significant effect of OS and clinical response was demonstrated in RCC patients.

Colorectal cancer and immunity: What we know and perspectives

Strong evidence supports the concept of immunosurveillance and immunoediting in colorectal cancer. In particular, the density of T CD8⁺ and CD45⁺ lymphocyte infiltration was recently shown to have a better prognostic value than the classic tumor node metastasis classification factor. Other immune subsets, as macrophages, natural killer cells or unconventionnal lymphocytes, seem to play an important role. Induction of regulatory T cells (Tregs) or immunosuppressive molecules such as PD-1 or CTLA-4 and downregulation of antigen-presenting molecules are major escape mechanisms to antitumor immune response. The development of these mechanisms is a major obstacle to the establishment of an effective immune response, but also to the use of immunotherapy. Although immunotherapy is not yet routinely used in colorectal cancer, we now know that most treatments used (chemotherapy and biotherapy) have immunomodulatory effects, such as induction of immunogenic cell death by chemotherapy, inhibition of immunosuppression by antiangiogenic agents, and antibody-dependent cytotoxicity induced by cetuximab. Finally, many immunotherapy strategies are being developed and tested in phase I to III clinical trials. The most promising strategies are boosting the immune system with cytokines, inhibition of immunoregulatory checkpoints, vaccination with vectorized antigens, and adoptive cell therapy. Comprehension of antitumor immune response and combination of the different approaches of immunotherapy may allow the use of effective immunotherapy for treatment of colorectal cancer in the near future.

Combination of chemotherapy and immunotherapy for colon cancer in China: A meta-analysis

AIM: To investigate whether autologous dendritic cell (DC)-cytokine-induced killer (CIK) cell therapy is able to improve the therapeutic efficacy of chemotherapy in colon cancer.

METHODS: We conducted a systematic review of published papers from the sources of MEDLINE, the Cochrane Central Register of Controlled Trials, EMBASE, the Wanfang Database, the China Science and Technology Periodical Database and China Journal Net. Published data were extracted independently by two authors using predefined database templates. The quality of the data from individual papers was also assessed. The effects of chemotherapy were compared with those of chemotherapy in combination with DC-CIK immunotherapy. The pooled analysis was performed using the data from random or fixed-effect models.

RESULTS: Seven trials matched our inclusion criteria (n = 533). The overall analysis showed significant survival benefit [one-year overall survival (OS), P < 0.0001; two-year OS, P = 0.009; three-year OS, P = 0.002] in favor of DC-CIK immunotherapy combined with chemotherapy. Disease-free survival (DFS) rate was improved after the combination of DC-CIK immunotherapy and chemotherapy (one-year DFS, P < 0.0001; two-year DFS, P = 0.002; three-year DFS, P = 0.02). An improved overall response rate (P = 0.009) was also observed in patients who received DC-CIK therapy. Furthermore, the analysis of T-lymphocyte subsets in peripheral blood indicated that the number of CD4⁺ T cells significantly increased in the DC-CIK plus chemotherapy group (P < 0.05).

CONCLUSION: The combination of DC-CIK immunotherapy and chemotherapy was superior in prolonging the survival time and enhancing immunological responses.

Review article: antitumoural immunity in colorectal cancer - current and potential future implications in clinical practice

BACKGROUND

Most of the current research in gastrointestinal oncology is focused on biology of cancer itself, but there is growing interest in the patient's immune system response and its relation with cancer cells.

AIM

To review the impact of the antitumoural immune response on epidemiology, prognosis and treatment of colorectal cancer.

METHODS

Search of the literature published in English using the PubMed database.

RESULTS

The role of the immune system in the antitumoural immunosurveillance is clearly supported by the increased incidence of colorectal cancer and adenomatous polyps in immunosuppressed patients. Moreover, the degree of infiltration of the tumours by the immune cells has been shown to be a strong prognostic factor of both disease recurrence and survival. The immune system plays an important role in the chemotherapy-induced cell death. New therapeutic strategies targeting the antitumoural immunity are being currently investigated with promising results.

CONCLUSION

Better knowledge of antitumoural immune system can have a major impact on patients' management in daily clinical practice. Colorectal cancer screening is an important issue in immunosuppressed patients, and recommendations should be refined for selected high-risk patients. The use of an immune score to guide the therapeutic strategies in the adjuvant setting should be supported. Further and larger clinical trials are necessary to accelerate the development of innovative immune therapies.

Immunotherapy for gastrointestinal malignancies

BACKGROUND

Gastrointestinal (GI) cancers are the most common human tumors encountered worldwide. The majority of GI cancers are unresectable at the time of diagnosis, and in the subset of patients undergoing resection, few are cured. There is only a modest improvement in survival with the addition of modalities such as chemotherapy and radiation therapy. Due to an increasing global cancer burden, it is imperative to integrate alternative strategies to improve outcomes. It is well known that cancers possess diverse strategies to evade immune detection and destruction. This has led to the incorporation of various immunotherapeutic strategies, which enable reprogramming of the immune system to allow effective recognition and killing of GI tumors.

METHODS

A review was conducted of the results of published clinical trials employing immunotherapy for esophageal, gastroesophageal, gastric, hepatocellular, pancreatic, and colorectal cancers.

RESULTS

Monoclonal antibody therapy has come to the forefront in the past decade for the treatment of colorectal cancer. Immunotherapeutic successes in solid cancers such as melanoma and prostate cancer have led to the active investigation of immunotherapy for GI malignancies, with some promising results.

CONCLUSIONS

To date, monoclonal antibody therapy is the only immunotherapy approved by the US Food and Drug Administration for GI cancers. Initial trials validating new immunotherapeutic approaches, including vaccination-based and adoptive cell therapy strategies, for GI malignancies have demonstrated safety and the induction of antitumor immune responses. Therefore, immunotherapy is at the forefront of neoadjuvant as well as adjuvant therapies for the treatment and eradication of GI malignancies.

The many flavors of tumor-associated B cells

Little is known on the role of distinct B-cell subtypes in human malignancies. We have recently performed a multiplex characterization of B cells in patient-derived tumor-associated tissues, documenting the activation and antigen-driven differentiation of B cells in metastatic lymph nodes and neoplastic lesions. Here we discuss the role of B lymphocytes as antigen-presenting cells and catalysts of T cell-based immunotherapies in view of these findings.

Epigenetics and colorectal cancer pathogenesis

Colorectal cancer (CRC) develops through a multistage process that results from the progressive accumulation of genetic mutations, and frequently as a result of mutations in the Wnt signaling pathway. However, it has become evident over the past two decades that epigenetic alterations of the chromatin, particularly the chromatin components in the promoter regions of tumor suppressors and oncogenes, play key roles in CRC pathogenesis. Epigenetic regulation is organized at multiple levels, involving primarily DNA methylation and selective histone modifications in cancer cells. Assessment of the CRC epigenome has revealed that virtually all CRCs have aberrantly methylated genes and that the average CRC methylome has thousands of abnormally methylated genes. Although relatively less is known about the patterns of specific histone modifications in CRC, selective histone modifications and resultant chromatin conformation have been shown to act, in concert with DNA methylation, to regulate gene expression to mediate CRC pathogenesis. Moreover, it is now clear that not only DNA methylation but also histone modifications are reversible processes. The increased understanding of epigenetic regulation of gene expression in the context of CRC pathogenesis has led to development of epigenetic biomarkers for CRC diagnosis and epigenetic drugs for CRC therapy.

Myeloid-derived suppressor cells attenuate TH1 development through IL-6 production to promote tumor progression

Collaborative action between tumor cells and host-derived suppressor cells leads to peripheral tolerance of T cells to tumor antigens. Here, we showed that in tumor-bearing mice, generation of tumor antigen-specific effector T-helper cells (TH1) was significantly attenuated, and impaired TH1 differentiation was restored by the temporal blockade of interleukin (IL)-6 activity at the T-cell priming phase. Furthermore, we found that Gr-1(+) myeloid-derived suppressor cells (MDSC) served as a source of IL-6 in tumor-bearing mice. Adoptive transfer of effector CD4(+) T cells revealed that MDSC-sensitized effector CD4(+) T cells were less potent in mounting antitumor immune responses, although effector T cells generated together with Gr-1(+) cells from tumor-free mice eradicated established tumors. CD8(+) T cells, IFN-γ, and MHC-class II expression in host mice were indispensable for the antitumor activity initiated by effector CD4(+) T cells. Despite comparable suppressive activity of IL-6(+/+) and IL-6(-/-) MDSC on primary T-cell activation, transfer of IL-6(+/+) MDSC, but not IL-6(-/-) MDSC, dampened the efficient induction of effector TH1 cells and counteracted CD4(+) T cell-mediated antitumor immunity including cognate help for CD8(+) T cells in vivo. These findings suggest that, apart from the inhibitory effects on primary T-cell activation, MDSC promote tumor progression by attenuating functional differentiation of tumor-specific CD4(+) T cells into effector TH1 cells through IL-6 production to promote tumor progression. This novel mode of MDSC-induced tolerance of effector CD4(+) T cells should be considered as the basis for the rational design of effective T cell-mediated antitumor therapies.

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.

Adoptive cell therapy with autologous tumor-infiltrating lymphocytes and high-dose interleukin-2 for metastatic melanoma: The surgeon's perspective

Tumor-infiltrating lymphocytes (TILs) are produced by resecting tumor tissue and growing and expanding ex vivo large quantities of autologous T cells. Once the TILs are ready for infusion, the patient undergoes a non-myeloablative lympho-depleting course of chemotherapy and subsequent TIL infusion with high-dose bolus IL-2. This study reviews the surgical experience of the TIL program at the Chaim Sheba Cancer Research Center in Israel. Eligible patients underwent surgical consultation to determine what tumorectomy would be beneficial for harvesting appropriate tissue. Factors involved in the decision included tumor mass size, location and morbidity of the procedure. Between January 2006 and May 2010, 44 patients underwent 47 procedures of adoptive transfer of TILs. Three patients underwent the procedure twice for recurrence after initial good responses, including an additional surgical procedure to produce fresh tumor. Thirty-seven excisions were with general anesthesia and 10 were with local anesthesia. Of the 37 general anesthesia procedures, 27 were open procedures involving a thoracotomy, a laparotomy or dissection of a major lymph node basin. Ten used minimally invasive techniques such as thorascopy or laparoscopy. Tumorectomy sites included 18 lymph node metastasis, 13 subcutaneous nodules, 11 lung specimens and 5 abdominal visceral metastasis including 2 liver lesions. Surgical mortality and major morbidity was 0%. Minor morbidity included only wound complications. Maximal number of TILs were derived from lymph node specimens, while liver metastasis procured the fewest TILs. Adoptive cell transfer technology affords a maximal tumor response with minimal surgical morbidity in metastatic patients.

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.

Regulatory T cells in gastrointestinal tumors

Regulatory T cells (Tregs) have the ability to suppress the activity of most other lymphoid cells, as well as dendritic cells through cell-cell contact-dependent mechanisms, which have not yet been fully defined. Tregs are a key component of a functional immune system and Treg deficiency is associated with severe autoimmunity and allergies. However, Tregs specific for tumor-associated antigens are present in cancer patients and Tregs accumulate in many types of solid tumors, where they probably act to promote tumor escape from cytotoxic immune responses. Indeed, some studies even show a negative correlation between Treg infiltration and survival of the patient. Several studies indicate an active recruitment of Tregs to the tumor site and the mechanisms of Treg accumulation are starting to be better understood as a result of more detailed analysis of their adhesion molecule and chemokine receptor expression. In addition, in gastrointestinal tumors there is an increase in tumor-associated Tregs, but intriguingly, Treg infiltration into colorectal adenocarcinomas is associated with improved prognosis. In this article, we will review the proposed mechanisms of immune suppression by tumor-associated Tregs, how the tumor microenvironment favors immune evasion and Treg induction, the tumor-homing mechanisms of Tregs and how Tregs affect progression of gastric and colorectal tumors.

Is secretion of tumour-specific antigen important for cancer eradication by CD4(+) T cells?--Implications for cancer immunotherapy by adoptive T cell transfer

The potential for cancer immunotherapy by adoptive transfer of CD4(+) T cells is gaining increased attention. Most cancer cells lack major histocompatibility complex (MHC) class II molecules and cannot present tumour-specific antigens (TSA) directly to CD4(+) T cells. We have reported that tumour-specific CD4(+) T cells collaborate with macrophages and dendritic cells. These professional antigen-presenting cells endocytose and process TSA to display antigenic peptides on their MHC class II molecules for indirect cancer cell recognition by CD4(+) T cells. We hypothesized that this critical step may depend on secretion of TSA by cancer cells. This was investigated in a mouse model for myeloma immunosurveillance mediated by CD4(+) T cells. From this study, several conclusions could be drawn. First, TSA secretion facilitates cancer immunosurveillance. Second, TSA secretion results in stronger activation of naïve tumour-specific CD4(+) T cells in lymph nodes. Third, TSA concentration within the tumour extracellular matrix must reach a certain threshold to allow successful cancer immunosurveillance. Fourth, treatment by local injection of purified TSA enhances immunity against cancer cells that do not secrete TSA. Fifth, secretion of TSA by at least some cancer cells within a tumour favours antitumour immunity. Therefore, we propose that CD4(+) T cells that recognize secreted TSA may be superior for immunotherapy by T cell transfer, because the local extracellular antigen concentration will be higher for secreted TSA. Thus, it is anticipated that secreted TSA will be more readily detected in vivo by transferred CD4(+) T cells, resulting in more efficient tumour eradication.

Multiparameter analysis of cellular immunity in patients with colorectal cancer

AIM: To compare the proportions of CD4⁺, CD8⁺ T cells, NK cells, B cells, and CD4⁺CD25^HighCD127^low Treg cells and Th/Treg ratio in the peripheral blood of patients with colorectal cancer and healthy controls to investigate the immune status in patients with colorectal cancer.

METHODS: Flow cytometry was used to analyze the proportions of CD4⁺, CD8⁺ T cells, NK cells, B cells, and CD4⁺CD25^HighCD127^low Treg cells and Th/Treg ratio in the peripheral blood from 100 patients with non-metastatic colorectal cancer, 100 patients with metastatic colorectal cancer, and 100 healthy controls. One-way ANOVA was used to study the changes in the above immunity parameters.

RESULTS: The proportion of CD4⁺CD25^HighCD127^low Treg cells was significantly higher in patients with metastatic colorectal cancer than in health controls and patients with non-metastatic colorectal cancer (7.72% ± 2.20% vs 6.08% ± 1.47%, 5.91% ± 1.55%, both P < 0.05), while that of CD4⁺ T cells was statistically lower in patients with metastatic colorectal cancer than in the other two groups of subjects (34.04% ± 8.71% vs 37.83% ± 7.62%, 37.68% ± 8.89%, both P < 0.05). The Th/Treg ratio was also significantly lower in patients with metastatic colorectal cancer than in health controls and patients with non-metastatic colorectal cancer (4.70 ± 1.72 vs 6.47 ± 2.54, 6.81 ± 4.09, both P < 0.05). There were no statistical differences in the proportions of CD8⁺ T cells, NK cells and B cells between patients with colorectal cancer and healthy controls.

CONCLUSION: Abnormal immune status was observed in patients with metastatic colorectal cancer.

TNFα cooperates with IFN-γ to repress Bcl-xL expression to sensitize metastatic colon carcinoma cells to TRAIL-mediated apoptosis

Background

TNF-related apoptosis-inducing ligand (TRAIL) is an immune effector molecule that functions as a selective anti-tumor agent. However, tumor cells, especially metastatic tumor cells often exhibit a TRAIL-resistant phenotype, which is currently a major impediment in TRAIL therapy. The aim of this study is to investigate the synergistic effect of TNFα and IFN-γ in sensitizing metastatic colon carcinoma cells to TRAIL-mediated apoptosis.

Methodology/Principal Findings

The efficacy and underlying molecular mechanism of cooperation between TNFα and IFN-γ in sensitizing metastatic colon carcinoma cells to TRAIL-mediated apoptosis were examined. The functional significance of TNFα- and IFN-γ-producing T lymphocyte immunotherapy in combination with TRAIL therapy in suppression of colon carcinoma metastasis was determined in an experimental metastasis mouse model. We observed that TNFα or IFN-γ alone exhibits minimal sensitization effects, but effectively sensitized metastatic colon carcinoma cells to TRAIL-induced apoptosis when used in combination. TNFα and IFN-γ cooperate to repress Bcl-xL expression, whereas TNFα represses Survivin expression in the metastatic colon carcinoma cells. Silencing Bcl-xL expression significantly increased the metastatic colon carcinoma cell sensitivity to TRAIL-induced apoptosis. Conversely, overexpression of Bcl-xL significantly decreased the tumor cell sensitivity to TRAIL-induced apoptosis. Furthermore, TNFα and IFN-γ also synergistically enhanced TRAIL-induced caspase-8 activation. TNFα and IFN-γ was up-regulated in activated primary and tumor-specific T cells. TRAIL was expressed in tumor-infiltrating immune cells in vivo, and in tumor-specific cytotoxic T lymphocytes (CTL) ex vivo. Consequently, TRAIL therapy in combination with TNFα/IFN-γ-producing CTL adoptive transfer immunotherapy effectively suppressed colon carcinoma metastasis in vivo.

Conclusions/Significance

TNFα and IFN-γ cooperate to overcome TRAIL resistance at least partially through enhancing caspase 8 activation and repressing Bcl-xL expression. Combined CTL immunotherapy and TRAIL therapy hold great promise for further development for the treatment of metastatic colorectal cancer.

Role of apoptosis resistance in immune evasion and metastasis of colorectal cancer

The host immune system functions as a guardian against tumor development. It has been demonstrated that cytotoxic T lymphocyte (CTL)-mediated cytotoxic pathways function to inhibit or delay human colorectal cancer development. However, the host anti-tumor immune responses also 'edit' the tumor and select for more aggressive variants, resulting in immune evasion and tumor escape. Fas is a death receptor that mediates one of the major cytotoxic effector mechanisms of the CTLs. Fas is highly expressed in normal human colon epithelial cells but is frequently silenced in colorectal carcinoma, especially in metastatic colorectal carcinoma, suggesting that loss of Fas expression and function may be an immune evasion and tumor escape mechanism. In addition, recent studies indicated that Fas also mediates cellular proliferation signaling pathways to promote tumor development. Therefore, the death receptor Fas may not only transduce death signals to suppress tumor development but also activate cellular proliferation and the migration process to promote tumor growth and progression. Thus, understanding the mechanisms by which the Fas receptor and its associated protein complex transduces the death and survival signals may identify molecular targets for the development of therapeutic strategy to enhance the Fas-mediated death signals to increase the efficacy of cancer immunotherapy.