Characterization of dendritic cells in differentiated thyroid cancer

Cross-Talk Between Cancer and Its Cellular Environment-A Role in Cancer Progression

The tumor microenvironment is a dynamic and complex three-dimensional network comprising the extracellular matrix and diverse non-cancerous cells, including fibroblasts, adipocytes, endothelial cells and various immune cells (lymphocytes T and B, NK cells, dendritic cells, monocytes/macrophages, myeloid-derived suppressor cells, and innate lymphoid cells). A constantly and rapidly growing number of studies highlight the critical role of these cells in shaping cancer survival, metastatic potential and therapy resistance. This review provides a synthesis of current knowledge on the modulating role of the cellular microenvironment in cancer progression and response to treatment.

Appraising the effectiveness of immune cells on thyroid cancer: a Mendelian randomization study

BACKGROUND

The intricate interplay between the immune system and tumor plays a pivotal role in thyroid cancer (TC) pathogenesis, potentially influencing both the causation and therapeutic outcomes. Despite extensive research, existing literature offers ambiguous insights regarding the association between immune cell traits and thyroid cancer progression.

METHODS

To elucidate the potential causal relationships, we conducted an integrated two-sample Mendelian randomization (MR) analysis. This study utilized publicly genetic datasets to explore the causalities between 731 immune cell traits (categorized into four trait types across seven panels) and thyroid cancer. We ensured the robustness of our findings through comprehensive sensitivity analyses, meticulously assessing potential sources of bias such as pleiotropy.

RESULTS

After False Discovery Rate (FDR) correction, six immune cell traits were identified to be significantly associated with thyroid cancer risk (Inverse Variance Weighted, IVW): Absolute count of gamma delta T cells/ T-cell receptor gamma delta absolute count (TCRgd AC) 0.8464 (OR95% CI = 0.7477-0.9580, P = 0.0083, PFDR = 0.0103); CD8 on bright CD8 cells (CD8 on CD8br) 0.8867 (OR95% CI = 0.8159-0.9637, P = 0.0047, PFDR = 0.0093); CD127 on CD45RA negative CD4 T cells not regulatory T cells (CD127 on CD45RA- CD4 not Treg) 0.8969 (OR95% CI = 0.8192-0.9820, P = 0.0186, PFDR = 0.0186); CD80 on CD62L positive plasmacytoid dendritic cells (CD80 on CD62L+ plasmacytoid DC) 1.1091 (OR95% CI = 1.0267-1.1982, P = 0.0086, PFDR = 0.0103); CD80 on plasmacytoid DC 1.1283 (OR95% CI = 1.0462-1.2168, P = 0.0017, PFDR = 0.0093); Side scatter-area on bright CD8 cells (SSC - A on CD8br) 1.1622 (OR95% CI = 1.0507-1.2854, P = 0.0035, PFDR = 0.0093).

CONCLUSIONS

Our study demonstrated the causalities between immune cell traits and thyroid cancers by Mendelian randomization study, thus guiding future mechanism studies.

Harnessing Immunity to Treat Advanced Thyroid Cancer

The incidence of thyroid cancer (TC) has increased over the past 30 years. Although differentiated thyroid cancer (DTC) has a good prognosis in most patients undergoing total thyroidectomy followed by radioiodine therapy (RAI), 5-10% of patients develop metastasis. Anaplastic thyroid cancer (ATC) has a low survival rate and few effective treatments have been available to date. Recently, tyrosine kinase inhibitors (TKIs) have been successfully applied to RAI-resistant or non-responsive TC to suppress the disease. However, TC eventually develops resistance to TKIs. Immunotherapy is a promising treatment for TC, the majority of which is considered an immune-hot malignancy. Immune suppression by TC cells and immune-suppressing cells, including tumor-associated macrophages, myeloid-derived suppressor cells, and regulatory T cells, is complex and dynamic. Negative immune checkpoints, cytokines, vascular endothelial growth factors (VEGF), and indoleamine 2,3-dioxygenase 1 (IDO1) suppress antitumor T cells. Basic and translational advances in immune checkpoint inhibitors (ICIs), molecule-targeted therapy, tumor-specific immunotherapy, and their combinations have enabled us to overcome immune suppression and activate antitumor immune cells. This review summarizes current findings regarding the immune microenvironment, immunosuppression, immunological targets, and immunotherapy for TC and highlights the potential efficacy of immunotherapy.

Upregulation of dendrocyte-expressed seven transmembrane protein is associated with unfavorable outcomes in differentiated thyroid cancer

PURPOSE

Dendritic cell infiltrates are increased in thyroid cancer but may have a defective ability to provoke effective immune responses. In this study, we aimed to identify potential thyroid cancer biomarkers linked to dendritic cell development and evaluate their prognostic relevance.

METHODS

Through a bioinformatics search, we identified the dendrocyte-expressed seven transmembrane protein (DCSTAMP) as a prognostic gene involved in dendritic cell differentiation for thyroid cancer. Immunohistochemical analyses of DCSTAMP expression were performed and correlated with clinical outcomes.

RESULTS

DCSTAMP was overexpressed in a variety of types of thyroid cancers, while normal thyroid tissue or benign thyroid lesions exhibited low or undetectable DCSTAMP immunoreactivity. The results of automated quantification were consistent with subjective semiquantitative scoring. Among 144 patients with differentiated thyroid cancer, high DCSTAMP expression was associated with papillary tumor type (p < 0.001), extrathyroidal extension (p = 0.007), lymph node metastasis (p < 0.001), and BRAF V600E mutation (p = 0.029). Patients with tumors showing high DCSTAMP expression had shorter overall (p = 0.027) and recurrence-free (p = 0.042) survival.

CONCLUSION

This study provides the first evidence of DCSTAMP overexpression in thyroid cancer. Apart from the prognostic implications, studies are needed to explore its potential immunomodulatory role in thyroid cancer.

Crosstalk between Thyroid Carcinoma and Tumor-Correlated Immune Cells in the Tumor Microenvironment

Thyroid cancer (TC) is the most common malignancy in the endocrine system. Although most TC can achieve a desirable prognosis, some refractory thyroid carcinomas, including radioiodine-refractory differentiated thyroid cancer, as well as anaplastic thyroid carcinoma, face a myriad of difficulties in clinical treatment. These types of tumors contribute to the majority of TC deaths due to limited initial therapy, recurrence, and metastasis of the tumor and tumor resistance to current clinically targeted drugs, which ultimately lead to treatment failure. At present, a growing number of studies have demonstrated crosstalk between TC and tumor-associated immune cells, which affects tumor deterioration and metastasis through distinct signal transduction or receptor activation. Current immunotherapy focuses primarily on cutting off the interaction between tumor cells and immune cells. Since the advent of immunotherapy, scholars have discovered targets for TC immunotherapy, which also provides new strategies for TC treatment. This review methodically and intensively summarizes the current understanding and mechanism of the crosstalk between distinct types of TC and immune cells, as well as potential immunotherapy strategies and clinical research results in the area of the tumor immune microenvironment. We aim to explore the current research advances to formulate better individualized treatment strategies for TC patients and to provide clues and references for the study of potential immune checkpoints and the development of immunotherapy technologies.

Inflammatory Components of the Thyroid Cancer Microenvironment: An Avenue for Identification of Novel Biomarkers

The incidence of thyroid cancer in the United States is on the rise with an appreciably high disease recurrence rate of 20-30%. Anaplastic thyroid cancer (ATC), although rare in occurrence, is an aggressive form of cancer with limited treatment options and bleak cure rates. This chapter uses discussions of in vitro models that are representative of papillary, anaplastic, and follicular thyroid cancer to evaluate the crosstalk between specific cells of the tumor microenvironment (TME), which serves as a highly heterogeneous realm of signaling cascades and metabolism that are associated with tumorigenesis. The cellular constituents of the TME carry out varying characteristic immunomodulatory functions that are discussed throughout this chapter. The aforementioned cell types include cancer-associated fibroblasts (CAFs), endothelial cells (ECs), and cancer stem cells (CSCs), as well as specific immune cells, including natural killer (NK) cells, dendritic cells (DCs), mast cells, T regulatory (Treg) cells, CD8+ T cells, and tumor-associated macrophages (TAMs). TAM-mediated inflammation is associated with a poor prognosis of thyroid cancer, and the molecular basis of the cellular crosstalk between macrophages and thyroid cancer cells with respect to inducing a metastatic phenotype is not yet known. The dynamic nature of the physiological transition to pathological metastatic phenotypes when establishing the TME encompasses a wide range of characteristics that are further explored within this chapter, including the roles of somatic mutations and epigenetic alterations that drive the genetic heterogeneity of cancer cells, allowing for selective advantages that aid in their proliferation. Induction of these proliferating cells is typically accomplished through inflammatory induction, whereby chronic inflammation sets up a constant physiological state of inflammatory cell recruitment. The secretions of these inflammatory cells can alter the genetic makeup of proliferating cells, which can in turn, promote tumor growth.This chapter also presents an in-depth analysis of molecular interactions within the TME, including secretory cytokines and exosomes. Since the exosomal cargo of a cell is a reflection and fingerprint of the originating parental cells, the profiling of exosomal miRNA derived from thyroid cancer cells and macrophages in the TME may serve as an important step in biomarker discovery. Identification of a distinct set of tumor suppressive miRNAs downregulated in ATC-secreted exosomes indicates their role in the regulation of tumor suppressive genes that may increase the metastatic propensity of ATC. Additionally, the high expression of pro-inflammatory cytokines in studies looking at thyroid cancer and activated macrophage conditioned media suggests the existence of an inflammatory TME in thyroid cancer. New findings are suggestive of the presence of a metastatic niche in ATC tissues that is influenced by thyroid tumor microenvironment secretome-induced epithelial to mesenchymal transition (EMT), mediated by a reciprocal interaction between the pro-inflammatory M1 macrophages and the thyroid cancer cells. Thus, targeting the metastatic thyroid carcinoma microenvironment could offer potential therapeutic benefits and should be explored further in preclinical and translational models of human metastatic thyroid cancer.

Disruption of Cell-Cell Communication in Anaplastic Thyroid Cancer as an Immunotherapeutic Opportunity

Thyroid cancer incidence is increasing at an alarming rate, almost tripling every decade. About 44,280 new cases of thyroid cancer (12,150 in men and 32,130 in women) are estimated to be diagnosed in 2021, with an estimated death toll of around 2200. Although most thyroid tumors are treatable and associated with a favorable outcome, anaplastic thyroid cancer (ATC) is extremely aggressive with a grim prognosis of 6-9 months post-diagnosis. A large contributing factor to this aggressive nature is that ATC is completely refractory to mainstream therapies. Analysis of the tumor microenvironment (TME) associated with ATC can relay insight to the pathological realm that encompasses tumors and aids in cancer progression and proliferation. The TME is defined as a complex niche that surrounds a tumor and involves a plethora of cellular components whose secretions can modulate the environment in order to favor tumor progression. The cellular heterogeneity of the TME contributes to its dynamic function due to the presence of both immune and nonimmune resident, infiltrating, and interacting cell types. Associated immune cells discussed in this chapter include macrophages, dendritic cells (DCs), natural killer (NK) cells, and tumor-infiltrating lymphocytes (TILs). Nonimmune cells also play a role in the establishment and proliferation of the TME, including neuroendocrine (NE) cells, adipocytes, endothelial cells (ECs), mesenchymal stem cells (MSCs), and fibroblasts. The dynamic nature of the TME contributes greatly to cancer progression.Recent work has found ATC tissues to be defined by a T cell-inflamed "hot" tumor immune microenvironment (TIME) as evidenced by presence of CD3+ and CD8+ T cells. These tumor types are amenable to immune checkpoint blockade (ICB) therapy. This therapeutic avenue, as of 2021, has remained unexplored in ATC. New studies should seek to explore the therapeutic feasibility of a combination therapy, through the use of a small molecule inhibitor with ICB in ATC. Screening of in vitro model systems representative of papillary, anaplastic, and follicular thyroid cancer explored the expression of 29 immune checkpoint molecules. There are higher expressions of HVEM, BTLA, and CD160 in ATC cell lines when compared to the other TC subtypes. The expression level of HVEM was more than 30-fold higher in ATC compared to the others, on average. HVEM is a member of tumor necrosis factor (TNF) receptor superfamily, which acts as a bidirectional switch through interaction with BTLA, CD160, and LIGHT, in a cis or trans manner. Given the T cell-inflamed hot TIME in ATC, expression of HVEM on tumor cells was suggestive of a possibility for complex crosstalk of HVEM with inflammatory cytokines. Altogether, there is emerging evidence of a T cell-inflamed TIME in ATC along with the expression of immune checkpoint proteins HVEM, BTLA, and CD160 in ATC. This can open doors for combination therapies using small molecule inhibitors targeting downstream effectors of MAPK pathway and antagonistic antibodies targeting the HVEM/BTLA axis as a potentially viable therapeutic avenue for ATC patients. With this being stated, the development of adaptive resistance to targeted therapies is inevitable; therefore, using a combination therapy that targets the TIME can serve as a preemptive tactic against the characteristic therapeutic resistance that is seen in ATC. The dynamic nature of the TME, including the immune cells, nonimmune cells, and acellular components, can serve as viable targets for combination therapy in ATC. Understanding the complex interactions of these associated cells and the paradigm in which their secretions and components can serve as immunomodulators are critical points of understanding when trying to develop therapeutics specifically tailored for the anaplastic thyroid carcinoma microenvironment.

Immune Cell Confrontation in the Papillary Thyroid Carcinoma Microenvironment

Background

Papillary thyroid cancer has been associated with chronic inflammation. A systematic understanding of immune cell infiltration in PTC is essential for subsequent immune research and new diagnostic and therapeutic strategies.

Methods

Three different algorithms, single-sample gene set enrichment analysis (ssGSEA), immune cell marker and CIBERSORT, were used to evaluate immune cell infiltration levels (abundance and proportion) in 10 data sets (The Cancer Genome Atlas [TCGA], GSE3467, GSE3678, GSE5364, GSE27155, GSE33630, GSE50901, GSE53157, GSE58545, and GSE60542; a total of 799 PTC and 194 normal thyroid samples). Consensus unsupervised clustering divided PTC patients into low-immunity and high-immunity groups. Weighted gene coexpression network analysis (WGCNA) and gene set enrichment analysis (GSEA) were used to analyze the potential mechanisms causing differences in the immune response.

Results

Compared with normal tissues, PTC tissues had a higher overall immune level and higher abundance levels and proportions of M2 macrophages, Tregs, monocytes, neutrophils, dendritic cells (DCs), mast cells (MCs), and M0 macrophages. Compared with early PTC, advanced PTC showed higher immune infiltration and higher abundance levels and proportions of M2 macrophages, Tregs, monocytes, neutrophils, DCs, MCs, and M0 macrophages. Compared to the low-immunity group, the high-immunity group exhibited more advanced stages, larger tumor sizes, greater lymph node metastases, higher tall-cell PTCs, lower follicular PTC proportions, more BRAF mutations, and fewer RAS mutations. Epstein-Barr virus (EBV) infection was the most significantly enriched Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway for key module genes.

Conclusions

In human PTC, M2 macrophages, Tregs, monocytes, neutrophils, DCs, MCs, and M0 macrophages appear to play a tumor-promoting role, while M1 macrophages, CD8+ T cells, B cells, NK cells, and T follicular helper (TFH) cells (including eosinophils, γδ T cells, and Th17 cells with weak supporting evidence) appear to play an antitumor role. During the occurrence and development of PTC, the overall immune level was increased, and the abundance and proportion of tumor-promoting immune cells were significantly increased, indicating that immune escape had been aggravated. Finally, we speculate that EBV may play an important role in changing the immune microenvironment of PTC tumors.

Immune and Inflammatory Cells in Thyroid Cancer Microenvironment

A hallmark of cancer is the ability of tumor cells to avoid immune destruction. Activated immune cells in tumor microenvironment (TME) secrete proinflammatory cytokines and chemokines which foster the proliferation of tumor cells. Specific antigens expressed by cancer cells are recognized by the main actors of immune response that are involved in their elimination (immunosurveillance). By the recruitment of immunosuppressive cells, decreasing the tumor immunogenicity, or through other immunosuppressive mechanisms, tumors can impair the host immune cells within the TME and escape their surveillance. Within the TME, cells of the innate (e.g., macrophages, mast cells, neutrophils) and the adaptive (e.g., lymphocytes) immune responses are interconnected with epithelial cancer cells, fibroblasts, and endothelial cells via cytokines, chemokines, and adipocytokines. The molecular pattern of cytokines and chemokines has a key role and could explain the involvement of the immune system in tumor initiation and progression. Thyroid cancer-related inflammation is an important target for diagnostic procedures and novel therapeutic strategies. Anticancer immunotherapy, especially immune checkpoint inhibitors, unleashes the immune system and activates cytotoxic lymphocytes to kill cancer cells. A better knowledge of the molecular and immunological characteristics of TME will allow novel and more effective immunotherapeutic strategies in advanced thyroid cancer.

The Immune Landscape of Thyroid Cancer in the Context of Immune Checkpoint Inhibition

Immune cells play critical roles in tumor prevention as well as initiation and progression. However, immune-resistant cancer cells can evade the immune system and proceed to form tumors. The normal microenvironment (immune cells, fibroblasts, blood and lymphatic vessels, and interstitial extracellular matrix (ECM)) maintains tissue homeostasis and prevents tumor initiation. Inflammatory mediators, reactive oxygen species, cytokines, and chemokines from an altered microenvironment promote tumor growth. During the last decade, thyroid cancer, the most frequent cancer of the endocrine system, has emerged as the fifth most incident cancer in the United States (USA), and its incidence is steadily growing. Inflammation has long been associated with thyroid cancer, raising critical questions about the role of immune cells in its pathogenesis. A plethora of immune cells and their mediators are present in the thyroid cancer ecosystem. Monoclonal antibodies (mAbs) targeting immune checkpoints, such as mAbs anti-cytotoxic T lymphocyte antigen 4 (anti-CTLA-4) and anti-programmed cell death protein-1/programmed cell death ligand-1 (anti-PD-1/PD-L1), have revolutionized the treatment of many malignancies, but they induce thyroid dysfunction in up to 10% of patients, presumably by enhancing autoimmunity. Combination strategies involving immune checkpoint inhibitors (ICIs) with tyrosine kinase (TK) or serine/threonine protein kinase B-raf (BRAF) inhibitors are showing considerable promise in the treatment of advanced thyroid cancer. This review illustrates how different immune cells contribute to thyroid cancer development and the rationale for the antitumor effects of ICIs in combination with BRAF/TK inhibitors.

Papillary thyroid carcinoma behavior: clues in the tumor microenvironment

The prevalence of thyroid carcinoma is increasing and represents the most common endocrine malignancy, with papillary thyroid carcinoma (PTC) being the most frequent subtype. The genetic alterations identified in PTCs fail to distinguish tumors with different clinical behaviors, such as extra-thyroidal extension and lymph node metastasis. We hypothesize that the immune microenvironment may play a critical role in tumor invasion and metastasis. Computational immunogenomic analysis was performed on 568 PTC samples in The Cancer Genome Atlas using CIBERSORT, TIMER and TIDE deconvolution analytic tools for characterizing immune cell composition. Immune cell infiltrates were correlated with histologic type, mutational type, tumor pathologic T stage and lymph node N stage. Dendritic cells (DCs) are highly associated with more locally advanced tumor T stage (T3/T4, odds ratio (OR) = 2.6, CI = 1.4-4.5, P = 5.4 × 10-4). Increased dendritic cells (OR = 3.4, CI = 1.9-6.3, P = 5.5 × 10-5) and neutrophils (OR = 10.5, CI = 2.7-44, P = 8.7 × 10-4) significantly correlate with lymph node metastasis. In addition, dendritic cells positively correlate with tall cell morphology (OR = 4.5, CI = 1.6-13, P = 4.9 × 10-3) and neutrophils negatively correlate with follicular morphology (OR = 1.3 × 10-3, CI = 5.3 × 10-5-0.031, P = 4.1 × 10-5). TIDE analysis indicates an immune-exclusive phenotype that may be mediated by increased galectin-3 found in PTCs. Thus, characterization of the PTC immune microenvironment using three computational platforms shows that specific immune cells correlate with mutational type, histologic type, local tumor extent and lymph node metastasis. Immunologic evaluation of PTCs may provide a better indication of biologic behavior, resulting in the improved diagnosis and treatment of thyroid cancer.

Role of Chemokines in Thyroid Cancer Microenvironment: Is CXCL8 the Main Player?

Tumor-related inflammation does influence the biological behavior of neoplastic cells and ultimately the patient's outcome. With specific regard to thyroid cancer, the issue of tumor-associated inflammation has been extensively studied and recently reviewed. However, the role of chemokines, which play a crucial role in determining the immuno-phenotype of tumor-related inflammation, was not addressed in previous reviews on the topic. Experimental evidence shows that thyroid cancer cells actively secrete a wide spectrum of chemokines and, at least for some of them, solid scientific data support a role for these immune-active molecules in the aggressive behavior of the tumor. Our proposal for a review article on chemokines and thyroid cancer stems from the notion that chemokines, besides having the ability to attract and maintain immune cells at the tumor site, also produce several pro-tumorigenic actions, which include proangiogenetic, cytoproliferative, and pro-metastatic effects. Studies taking into account the role of CCL15, C-X-C motif ligand 12, CXCL16, CXCL1, CCL20, and CCL2 in the context of thyroid cancer will be reviewed with particular emphasis on CXCL8. The reason for focusing on CXCL8 is that this chemokine is the most studied one in human malignancies, displaying multifaceted pro-tumorigenic effects. These include enhancement of tumor cells growth, metastatization, and angiogenesis overall contributing to the progression of several cancers including thyroid cancer. We aim at reviewing current knowledge on the (i) ability of both normal and tumor thyroid cells to secrete CXCL8; (ii) direct/indirect pro-tumorigenic effects of CXCL8 demonstrated by in vitro and in vivo studies specifically performed on thyroid cancer cells; and (iii) pharmacologic strategies proven to be effective for lowering CXCL8 secretion and/or its effects on thyroid cancer cells.

The immune network in thyroid cancer

The immune system plays critical roles in tumor prevention, but also in its initiation and progression. Tumors are subjected to immunosurveillance, but cancer cells generate an immunosuppressive microenvironment that favors their escape from immune-mediated elimination. During chronic inflammation, immune cells can contribute to the formation and progression of tumors by producing mitogenic, prosurvival, proangiogenic and lymphangiogenic factors. Thyroid cancer is the most frequent type of endocrine neoplasia and is the most rapidly increasing cancer in the US. In this review, we discuss recent findings on how different immune cells and mediators can contribute to thyroid cancer development and progression.

CD1a-positive dendritic cell density predicts disease-free survival in papillary thyroid carcinoma

OBJECTIVES

Dendritic cells are common in inflammatory processes and in papillary thyroid carcinoma (PTC). Previous studies of the predictive value of S100-positive dendritic cell density for PTC outcome yielded inconsistent results. This study investigated the association of dendritic cell density and PTC recurrence based on CD1a expression.

METHODS

Representative slides from 56 consecutive specimens of PTC were immunostained with anti-CD1a antibodies, and dendritic cell density was analyzed by disease-free survival.

RESULTS

Dendritic cells were abundant in the tumoral tissue and sparse in the normal peritumoral tissue. Peritumoral dendritic cell density >1.1 cells/HPF was inversely associated with the risk of recurrence. Similar results were obtained with tumoral dendritic cell density (>12 cells/HPF), although the statistical significance was marginal.

CONCLUSIONS

High CD1a-positive dendritic cell density is associated with improved disease-free survival in PTC. The specificity of anti-CD1a immunostain for activated dendritic cells may explain the better outcome prediction in this study than in studies using S100 protein.

Breast Cancer Cell-Derived GM-CSF Licenses Regulatory Th2 Induction by Plasmacytoid Predendritic Cells in Aggressive Disease Subtypes

Reciprocal interactions between tumor cells and their microenvironment vitally impact tumor progression. In this study, we show that GM-CSF produced by primary breast tumor cells induced the activation of plasmacytoid predendritic cells (pDC), a cell type critical to anti-viral immunity. pDC that expressed the GM-CSF receptor were increased in breast tumors compared with noninvolved adjacent breast tissue. Tumor-activated pDC acquired naïve CD4(+) T-cell stimulatory capacity and promoted a regulatory Th2 response. Finally, the concomitant increase of GM-CSF and pDC was significantly associated with relatively more aggressive breast cancer subtypes. Our results characterize the first tumor-derived factor that can activate pDC to promote a regulatory Th2 response, with implications for therapeutic targeting of a tumor-immune axis of growing recognition in its significance to cancer.

Tumor-Associated Inflammatory Cells in Thyroid Carcinomas

The complex interactions between immune cells and tumor cells in cancer play a major role in tumor development and subsequent patient outcomes. Different types of tumor-associated inflammatory cells (TAICs), such as dendritic cells, macrophages, lymphocytes, and mast cells, have been recognized for many years in several tumors; however, the role of TAICs in cancer is still not completely understood. This review article focuses on the major types of TAICs, including their general role in cancer and, more specifically, their role and distribution in thyrocyte-derived carcinomas.

The role of chemoattractant receptors in shaping the tumor microenvironment

Chemoattractant receptors are a family of seven transmembrane G protein coupled receptors (GPCRs) initially found to mediate the chemotaxis and activation of immune cells. During the past decades, the functions of these GPCRs have been discovered to not only regulate leukocyte trafficking and promote immune responses, but also play important roles in homeostasis, development, angiogenesis, and tumor progression. Accumulating evidence indicates that chemoattractant GPCRs and their ligands promote the progression of malignant tumors based on their capacity to orchestrate the infiltration of the tumor microenvironment by immune cells, endothelial cells, fibroblasts, and mesenchymal cells. This facilitates the interaction of tumor cells with host cells, tumor cells with tumor cells, and host cells with host cells to provide a basis for the expansion of established tumors and development of distant metastasis. In addition, many malignant tumors of the nonhematopoietic origin express multiple chemoattractant GPCRs that increase the invasiveness and metastasis of tumor cells. Therefore, GPCRs and their ligands constitute targets for the development of novel antitumor therapeutics.

Immune response in thyroid cancer: widening the boundaries

The association between thyroid cancer and thyroid inflammation has been repeatedly reported and highly debated in the literature. In fact, both molecular and epidemiological data suggest that these diseases are closely related and this association reinforces that the immune system is important for thyroid cancer progression. Innate immunity is the first line of defensive response. Unlike innate immune responses, adaptive responses are highly specific to the particular antigen that induced them. Both branches of the immune system may interact in antitumor immune response. Major effector cells of the immune system that directly target thyroid cancer cells include dendritic cells, macrophages, polymorphonuclear leukocytes, mast cells, and lymphocytes. A mixture of immune cells may infiltrate thyroid cancer microenvironment and the balance of protumor and antitumor activity of these cells may be associated with prognosis. Herein, we describe some evidences that immune response may be important for thyroid cancer progression and may help us identify more aggressive tumors, sparing the vast majority of patients from costly unnecessary invasive procedures. The future trend in thyroid cancer is an individualized therapy.

Inflammatory immune cell responses and Toll-like receptor expression in synovial tissues in rheumatoid arthritis patients treated with biologics or DMARDs

Biologic antirheumatic drugs (BIO) have been reported to be potent therapeutic agents in the prevention of inflammatory joint destruction in rheumatoid arthritis (RA). The aim of this study was to investigate the immune-inflammatory cells, including Toll-like receptor (TLR)-equipped cells, in synovial tissue samples from RA patients on BIO compared to patients, who are only on conventional disease-modifying antirheumatic drug (DMARD). We analyzed immune-inflammatory cells in RA synovitis in patients of BIO group (n = 20) or DMARD group (n = 20). The grading scores of synovitis was 1.7 and 1.8 in each BIO and DMARD group and correlated best with the CD3(+) T (r = 0.71/0.70, p < 0.05) and CD20(+) B (r = 0.80/0.84, p < 0.05) cells in the both groups, but less well with the CD68(+) macrophages and S-100(+) dendritic cells (DCs). Interestingly, both T (116 vs. 242, p < 0.05) and B (80 vs. 142, p < 0.05) cell counts were lower in the BIO than in the DMARD group, whereas macrophage and DC counts did not differ. In contrast, the C-reactive protein (CRP) and disease activity score DAS28-CRP did not show clear-cut correlations with the inflammatory grade of the synovitis (r range, 0-0.35). Similar numbers of cells immunoreactive for TLR-1 to TLR-6 and TLR-9 were found in synovitis in both groups. Patients clinically responding to biologics might still have the potential of moderate/severe local joint inflammation, composed in particular of and possibly driven by the autoinflammatory TLR(+) cells.

The role of s100-positive dendritic cells in the prognosis of papillary thyroid carcinoma

Dendritic cells are potent antigen-presenting cells, common in inflammatory processes. We sought to investigate dendritic cell expression in papillary thyroid carcinoma and the relationship of dendritic cell density with the extent of thyroiditis and prognosis. Specimens from 69 consecutive patients with papillary thyroid carcinoma were immunohistochemically stained for the S100 protein, and the number of positive dendritic cells was counted. Cells were sparse in normal thyroid tissue and common in areas of thyroiditis and papillary carcinoma. Dendritic cell density in papillary carcinoma correlated with the thyroiditis grade and dendritic cell density in surrounding areas of thyroiditis. High-grade thyroiditis (42% of patients) was inversely associated with 3-year recurrence. Dendritic cell density was not associated with disease-free survival. The lack of prognostic value of dendritic cell density is not compliant with the only other relevant study in the literature, and further research is required.

Distribution of dendritic cell subtypes in primary oral squamous cell carcinoma is inconsistent with a functional response

Dendritic cell (DC) function will likely be important for immunological cancer therapies, but our knowledge of the roles of DCs in tumors is limited, in part because most studies were performed before DC subtypes were defined. We studied the distributions of immature epidermal, immature dermal, mature, and plasmacytoid DCs in 63 primary tumors and eight lymph node metastases from oral squamous cell carcinoma patients without evidence of distant metastasis. Immature CD207/Langerin+ and CD209/DC-SIGN+ DCs were present in the primary tumor region, but CD209/DC-SIGN+ cells rarely infiltrated the tumor. Mature DCs were rare, and presence of CD123+ plasmacytoid DCs was associated with poorer outcome. Unexpectedly, migration and maturation of DCs was associated with a worse outcome. Overall, the distribution of DC subtypes indicated that ineffective DC response to tumor is a failure of DC function rather than recruitment, suggesting that a strategy of shifting the balance of secreted factors in the tumor milieu may be more effective in restoring anti-tumor immune function than current methods restoring only one population of DCs to the immunosuppressive tumor region.

Expression of HDAC1 and CBP/p300 in human colorectal carcinomas

BACKGROUND

The histone-modifying enzymes histone deacetylase (HDAC) and histone acetyltransferase (HAT) control gene transcriptional activation and repression in human malignancies.

AIMS

To analyse the expression of HDAC/HAT-associated molecules such as HDAC1, CREB-binding protein (CBP) and p300 in human colorectal carcinomas, and investigate the relationship between their expression levels and clinicopathological parameters.

METHODS

Expression levels of HDAC1, CBP, and p300 in human colorectal cancer were investigated by immunohistochemistry. In situ hybridisation (ISH) and reverse transcription (RT)-PCR analyses were also carried out to confirm mRNA expression levels of these genes. Immunoreactivity was evaluated semi-quantitatively using a staining index (SI). The relationships between the SIs and clinicopathological findings were analysed and survival curves were calculated using the Kaplan-Meier method and log-rank tests.

RESULTS

The mean SIs for HDAC1, CBP, and p300 in this series of tumours were much higher than those in normal colonic mucosa. The presence of HDAC1 and CBP mRNAs on colorectal carcinoma cells as well as normal epithelial cells was confirmed by ISH analysis. A marked increase in p300 mRNA levels was detected in a majority of cases by RT-PCR. Among the patients with colorectal cancer, overexpression of p300 (SI>11.9) correlated with a poor prognosis, whereas high CBP expression levels (SI>16.6) indicated long-term survival.

CONCLUSION

Results showed the up-regulation of these three histone-modifying molecules in this series of colorectal cancers and suggested that monitoring of CBP and p300 may assist prediction of the prognosis in patients with colorectal adenocarcinoma.

Lymphocyte and immature dendritic cell infiltrates in differentiated, poorly differentiated, and undifferentiated thyroid carcinoma

OBJECTIVE

Numerous studies indicate that papillary thyroid carcinomas (PTC) with lymphocytic infiltrates are associated with a less extensive disease at diagnosis and improved disease-free survival. The infiltration of lymphocytes and immature CD1a+ dendritic cells (DC) was characterized in papillary, poorly differentiated (PDC), and undifferentiated (UC) carcinomas to evaluate their association with immunological infiltrates.

DESIGN

A series of 527 consecutive cases of thyroid carcinoma treated by total thyroidectomy were investigated by histopathological and immunohistochemical methods. The inflammatory infiltrate was quantified and typed in intratumoral and peritumoral tissues as well as in the controlateral lobe.

MAIN OUTCOME

The intratumoral infiltrate was strongly reduced or absent in PDC and UC. Intense infiltrates were detected in the PTC tall cell variant. In all histotypes, the extent of the intratumoral and peritumoral infiltrates was comparable. Immature DC were detected in PTCs and markedly reduced in PDC and UC. CD1a+ DCs were detected in a small percentage of PDC and UC.

CONCLUSIONS

Though a relationship between the extent of lymphocyte/DC infiltrates and the prognosis of PTCs could not be demonstrated, tumors with poor prognosis (PDCs, UCs) were characterized by markedly reduced lymphocyte/DC infiltrates. The study appears to confirm the protective role of DC and infiltrating lymphocytes against thyroid tumors.

Differences in dendritic cell activation and distribution after intravenous, intraperitoneal, and subcutaneous injection of lymphoma cells in mice

Dendritic cells (DCs) are key antigen-presenting cells (APCs) for initiating immune responses. However, in recent years, several groups have shown the defective function of DCs in tumor-bearing mice and in cancer patients. Our aim was to study the effects of lymphoma on DC differentiation and maturation and to assess the input of the tumor microenvironment and intravasation of tumor cells on DC precursors. EL-4 lymphoma cells were administrated via different routes (intraperitoneal, subcutaneous, and intravenous) and DC phenotype was investigated. Bone marrow-derived DCs and APCs obtained from the spleen were examined by flow cytometry, and immunohistochemical analysis of lymphoma, lungs, livers, and spleens was also performed. Intravenous administration of lymphoma cells induced suppression of DC differentiation and maturation assessed as a significant decrease of the IAb, CD80, CD86, CD11b, and CD11c expression on DCs and IAb on splenic APCs. Upregulation of APC differentiation was observed in animals after subcutaneous and intraperitoneal administration of lymphoma cells determined as increased expression of CD40 and CD86 in spleen APCs. These data suggest that the development of antitumor immune response might differ in the host receiving tumor vaccines via different injection routes.

Correlation of dendritic cell infiltration with active crypt inflammation in ulcerative colitis

The aim of this study was to evaluate the histological localization and phenotypic characteristics of infiltrating dendritic cells (DCs) and to examine the relationship between the degree of DC infiltration and the severity of inflammation in the colonic mucosa in ulcerative colitis (UC). Also explored was the expression of macrophage inflammatory protein-3alpha (MIP-3alpha), and its receptor CC-chemokine receptor 6 (CCR6), to evaluate the significance of immature DCs in the crypt inflammation evident in UC. There was a significant positive correlation between the number of infiltrating DCs and the degree of crypt inflammation, mononuclear cell infiltration, crypt atrophy, and comprehensive active inflammation. No significant correlation between the number of S-100 protein(+) cells and the severity of crypt atrophy was found. S-100 protein(+), MIP-3alpha(+), and CCR6(+) cells were frequently localized in or around the crypt with inflammation. MIP-3alpha(+) neutrophils and S-100 protein(+) CCR6(+) cells with dendritic morphology were detected in or around the crypt inflammation. Both S-100 protein(+) DCs and CCR6(+) cells were frequently clustered in the surface mucosa beneath the surface epithelium when the crypt was not inflamed. CD1a(+) Langerhans-cell-type DCs were not found in any of the tissues examined. These data indicate that DCs participate not only in chronic inflammation but also in active crypt inflammation.

An unusual case of undifferentiated carcinoma in situ with osteoclast-like giant cells of the pancreas

OBJECTIVES

We report an unusual case of undifferentiated carcinoma in situ with osteoclast-like giant cells (UC with OGCs) in a 68-year-old Japanese woman.

METHODS

Preoperative examinations revealed an unidentifiable mass lesion within the main pancreatic duct (MPD) in the pancreatic head, accompanied by a dilated MPD distal to the mass lesion, which was suspected to be an intraductal papillary-mucinous neoplasm of the main-duct type with acute pancreatitis because of an increased serum amylase level. A pancreaticoduodenectomy was performed.

RESULTS

A pencil-like tumor occupied the lumen of the MPD of the pancreatic head without a visible pancreatic parenchymal mass. The intraductal tumor included a sheet of spindle cells intermingled with scattered OGCs and pleomorphic giant cells. A poorly developed glandular pattern was occasionally observed at the tumor periphery. These findings were consistent with conventional UC with OGCs. However, extraductal invasion was not found in an extensive histopathologic examination, although focal intraductal spreading into the epithelium of the first branch of the MPD was observed.

CONCLUSIONS

Undifferentiated carcinoma with OGCs usually exhibits an invasive tumor at diagnosis and is associated with a poor outcome, but the patient is alive without recurrence 22 months after surgery. To our knowledge, this is the first reported case of UC in situ without evident extraductal invasion in English literature.

Thyroid cancer and the immune system: a model for effective immune surveillance

Differentiated thyroid cancers, including papillary and follicular variants, are a useful model with which to examine interactions between cancer and the immune system. Differentiated thyroid cancers are detected in only 20,000 individuals annually in the USA, but thyroid microcarcinomas (< 1 cm in diameter) are far more common. This suggests that the immune system might restrain the growth of these microcarcinomas. On the clinical level, patients with lymphocytes that infiltrate into papillary thyroid cancer have improved survival, supporting the notion that immune system activation might improve this. Together, these observations suggest that the growth and distant spread of thyroid carcinoma are suppressed by mechanisms of immune surveillance, possibly involving lymphocytes, macrophages and their secreted products. In this review, we examine the general hypothesis of immune surveillance and the data pertaining to the roles of lymphocytes, dendritic cells and cytokines in the immune response against thyroid cancers.

p21(WAF1) is required for butyrate-mediated growth inhibition of human colon cancer cells

A diet high in fiber is associated with a decreased incidence and growth of colon cancers. Butyrate, a four-carbon short-chain fatty acid product of fiber fermentation within the colon, appears to mediate these salutary effects. We sought to determine the molecular mechanism by which butyrate mediates growth inhibition of colonic cancer cells and thereby to elucidate the molecular link between a high-fiber diet and the arrest of colon carcinogenesis. We show that concomitant with growth arrest, butyrate induces p21 mRNA expression in an immediate-early fashion, through transactivation of a promoter cis-element(s) located within 1.4 kb of the transcriptional start site, independent of p53 binding. Studies using the specific histone hyperacetylating agent, trichostatin A, and histone deacetylase 1 indicate that growth arrest and p21 induction occur through a mechanism involving histone hyperacetylation. We show the critical importance of p21 in butyrate-mediated growth arrest by first confirming that stable overexpression of the p21 gene is able to cause growth arrest in the human colon carcinoma cell line, HT-29. Furthermore, using p21-deleted HCT116 human colon carcinoma cells, we provide convincing evidence that p21 is required for growth arrest to occur in response to histone hyperacetylation, but not for serum starvation nor postconfluent growth. Thus, p21 appears to be a critical effector of butyrate-induced growth arrest in colonic cancer cells, and may be an important molecular link between a high-fiber diet and the prevention of colon carcinogenesis.