Melanoma-specific tumor-infiltrating lymphocytes but not circulating melanoma-specific T cells may predict survival in resected advanced-stage melanoma patients

Targeting tumour metabolism in melanoma to enhance response to immune checkpoint inhibition: A balancing act

Immune checkpoint inhibition has transformed the treatment landscape of advanced melanoma and long-term survival of patients is now possible. However, at least half of the patients do not benefit sufficiently. Metabolic reprogramming is a hallmark of cancer cells and may contribute to both tumour growth and immune evasion by the tumour. Preclinical studies have indeed demonstrated that modulating tumour metabolism can reduce tumour growth while improving the functionality of immune cells. Since metabolic pathways are commonly shared between immune and tumour cells, it is essential to understand how modulating tumour metabolism in patients influences the intricate balance of pro-and anti-tumour immune effects in the tumour microenvironment. The key question is whether modulating tumour metabolism can inhibit tumour cell growth as well as facilitate an anti-tumour immune response. Here, we review current knowledge on the effect of tumour metabolism on the immune response in melanoma. We summarise metabolic pathways in melanoma and non-cancerous cells in the tumour microenvironment and discuss models and techniques available to study the metabolic-immune interaction. Finally, we discuss clinical use of these techniques to improve our understanding of how metabolic interventions can tip the balance towards a favourable, immune permissive microenvironment in melanoma patients.

Clinical protocol phase II study of tumor infiltrating lymphocytes in advanced tumors with alterations in the SWI/SNF complex: the TILTS study

The SWI/SNF complex is a chromatin remodeling complex comprised by several proteins such as SMARCA4 or SMARCB1. Mutations in its components can lead to the development of aggressive rhabdoid tumors such as epithelioid sarcoma, malignant rhabdoid tumor or small cell carcinoma of the ovary hypercalcemic type, among others. These malignancies tend to affect young patients and their prognosis is poor given the lack of effective treatments. Characteristically, these tumors are highly infiltrated by TILs, suggesting that some lymphocytes are recognizing tumor antigens. The use of those TILs as a therapeutic strategy is a promising approach worth exploring. Here, we report the clinical protocol of the TILTS study, a Phase II clinical trial assessing personalized adoptive cell therapy with TILs in patients affected by these tumor types.Clinical Trial Registration: 2023-504632-17-00 (www.clinicaltrialsregister.eu) (ClinicalTrials.gov).

Immunotherapy in Prostate Cancer: State of Art and New Therapeutic Perspectives

Prostate cancer (PC) is the most common type of tumor in men. In the early stage of the disease, it is sensitive to androgen deprivation therapy. In patients with metastatic castration-sensitive prostate cancer (mHSPC), chemotherapy and second-generation androgen receptor therapy have led to increased survival. However, despite advances in the management of mHSPC, castration resistance is unavoidable and many patients develop metastatic castration-resistant disease (mCRPC). In the past few decades, immunotherapy has dramatically changed the oncology landscape and has increased the survival rate of many types of cancer. However, immunotherapy in prostate cancer has not yet given the revolutionary results it has in other types of tumors. Research into new treatments is very important for patients with mCRPC because of its poor prognosis. In this review, we focus on the reasons for the apparent intrinsic resistance of prostate cancer to immunotherapy, the possibilities for overcoming this resistance, and the clinical evidence and new therapeutic perspectives regarding immunotherapy in prostate cancer with a look toward the future.

Proton beam therapy for cervical lymph node metastasis in an octogenarian with melanoma of unknown primary: a case report

An 80-year-old man with an approximately 3-cm mass in the right submandibular region presented to our institution. Magnetic resonance imaging revealed enlarged lymph nodes (LNs) in the right neck, and fluorine-18-2-deoxy-D-glucose (FDG) positron emission tomography (PET)/computed tomography (CT) indicated positive FDG accumulation in the right neck LNs only. Excisional biopsy was performed for suspected malignant lymphoma, and the biopsy revealed melanoma. Close examination of the skin, nasal cavity, oral pharyngeal and laryngeal cavities, and gastrointestinal tract were performed. No primary tumor was detected by these examinations, and the patient was diagnosed with cervical LN metastasis from melanoma of unknown primary of clinical stage T0N3bM0 stage IIIC. The patient refused cervical neck dissection because of his age and comorbidity of Alzheimer's disease and instead opted for proton beam therapy (PBT) at a total dose of 69 Gy (relative biological effectiveness) in 23 fractions. He did not receive any systemic therapy. The enlarged LNs shrunk slowly, and FDG PET/CT at 1 year after PBT showed that the right submandibular LN had shrunk from 27 to 7 mm in length, and there was no significant FDG accumulation. At 6 years and 4 months after PBT, the patient is alive without any recurrence.

The Immunotherapy and Immunosuppressive Signaling in Therapy-Resistant Prostate Cancer

Prostate cancer is one of the most common malignant tumors in men. Initially, it is androgen-dependent, but it eventually develops into castration-resistant prostate cancer (CRPC), which is incurable with current androgen receptor signaling target therapy and chemotherapy. Immunotherapy, specifically with immune checkpoint inhibitors, has brought hope for the treatment of this type of prostate cancer. Approaches such as vaccines, adoptive chimeric antigen receptor-T (CAR-T) cells, and immune checkpoint inhibitors have been employed to activate innate and adaptive immune responses to treat prostate cancer, but with limited success. Only Sipuleucel-T and the immune checkpoint inhibitor pembrolizumab are approved by the US FDA for the treatment of limited prostate cancer patients. Prostate cancer has a complex tumor microenvironment (TME) in which various immunosuppressive molecules and mechanisms coexist and interact. Additionally, prostate cancer is considered a “cold” tumor with low levels of tumor mutational burden, low amounts of antigen-presenting and cytotoxic T-cell activation, and high levels of immunosuppressive molecules including cytokines/chemokines. Thus, understanding the mechanisms of immunosuppressive signaling activation and immune evasion will help develop more effective treatments for prostate cancer. The purpose of this review is to summarize emerging advances in prostate cancer immunotherapy, with a particular focus on the molecular mechanisms that lead to immune evasion in prostate cancer. At the same time, we also highlight some potential therapeutic targets to provide a theoretical basis for the treatment of prostate cancer.

Evaluation of the TCR Repertoire as a Predictive and Prognostic Biomarker in Cancer: Diversity or Clonality?

Simple Summary

The TCR is the T cell antigen receptor, and it is responsible of the T cell activation, through the HLA-antigen complex recognition. Studying the TCR repertoire in patients with cancer can help to better understand the anti-tumoural responses and it has been suggested to have predictive and or/prognostic values, both for the disease and in response to treatments. The aim of this review is to summarize TCR repertoire studies performed in patients with cancer found in the literature, thoroughly analyse the different factors that can be involved in shaping the TCR repertoire, and draw the current conclusions in this field, especially focusing on whether the TCR diversity—or its opposite, the clonality—can be used as predictors or prognostic biomarkers of the disease.

Abstract

T cells play a vital role in the anti-tumoural response, and the presence of tumour-infiltrating lymphocytes has shown to be directly correlated with a good prognosis in several cancer types. Nevertheless, some patients presenting tumour-infiltrating lymphocytes do not have favourable outcomes. The TCR determines the specificities of T cells, so the analysis of the TCR repertoire has been recently considered to be a potential biomarker for patients’ progression and response to therapies with immune checkpoint inhibitors. The TCR repertoire is one of the multiple elements comprising the immune system and is conditioned by several factors, including tissue type, tumour mutational burden, and patients’ immunogenetics. Its study is crucial to understanding the anti-tumoural response, how to beneficially modulate the immune response with current or new treatments, and how to better predict the prognosis. Here, we present a critical review including essential studies on TCR repertoire conducted in patients with cancer with the aim to draw the current conclusions and try to elucidate whether it is better to encounter higher clonality with few TCRs at higher frequencies, or higher diversity with many different TCRs at lower frequencies.

Bedside formulation of a personalized multi-neoantigen vaccine against mammary carcinoma

Background

Harnessing the immune system to purposely recognize and destroy tumors represents a significant breakthrough in clinical oncology. Non-synonymous mutations (neoantigenic peptides) were identified as powerful cancer targets. This knowledge can be exploited for further improvements of active immunotherapies, including cancer vaccines, as T cells specific for neoantigens are not attenuated by immune tolerance mechanism and do not harm healthy tissues. The current study aimed at developing an optimized multitarget vaccine using short or long neoantigenic peptides utilizing virus-like particles (VLPs) as an efficient vaccine platform.

Methods

Mutations of murine mammary carcinoma cells were identified by integrating mass spectrometry-based immunopeptidomics and whole exome sequencing. Neoantigenic peptides were synthesized and covalently linked to virus-like nanoparticles using a Cu-free click chemistry method for easy preparation of vaccines against mouse mammary carcinoma.

Results

As compared with short peptides, vaccination with long peptides was superior in the generation of neoantigen-specific CD4⁺ and CD8⁺ T cells, which readily produced interferon gamma (IFN-γ) and tumor-necrosis factor α (TNF-α). The resulting anti-tumor effect was associated with favorable immune re-polarization in the tumor microenvironment through reduction of myeloid-derived suppressor cells. Vaccination with long neoantigenic peptides also decreased post-surgical tumor recurrence and metastases, and prolonged mouse survival, despite the tumor’s low mutational burden.

Conclusion

Integrating mass spectrometry-based immunopeptidomics and whole exome sequencing is an efficient approach for identifying neoantigenic peptides. Our multitarget VLP-based vaccine shows a promising anti-tumor effect in an aggressive murine mammary carcinoma model. Future clinical application using this strategy is readily feasible and practical, as click chemistry coupling of personalized synthetic peptides to the nanoparticles can be done at the bedside directly before injection.

Combined immune checkpoint inhibitors of CTLA4 and PD-1 for hepatic melanoma of unknown primary origin: A case report

BACKGROUND

Melanoma is uncommonly found in lymph nodes, subcutaneous tissue, or visceral organs without a primary lesion, where it is identified as metastatic melanoma with unknown primary (MUP). Hepatic MUP is extremely rare and has a poor prognosis. There is limited information on its pathogenesis, clinical and imaging features, and pathological findings. There are no guidelines for the use of immune checkpoint inhibitors (ICIs) in hepatic MUP, and the treatment outcome has rarely been reported.

CASE SUMMARY

A 42-year-old woman presented to our hospital with hepatic tumors found incidentally during a routine check-up. Contrast-enhanced abdominal com-puterized tomography showed multiple mass lesions in the liver. Pathological results revealed melanoma, which was confirmed by immunohistochemical staining for HMB-45(+), Melan-A(+), S-100(+), and SOX10(+). There was no evidence of primary cutaneous, ocular, gastrointestinal, or anal lesion on a comprehensive examination. The patient was diagnosed with hepatic MUP. She received combined antibodies against cytotoxic T-lymphocyte-associated antigen 4 (CTLA-4, ipilimumab) and programmed death protein-1 (PD-1, nivolumab). She died of hepatic failure 9 mo after hepatic MUP was diagnosed. This the first case of hepatic MUP treated with combined ipilimumab and nivolumab, who showed better outcome than previous cases.

CONCLUSION

Combined ICIs of PD-1 and CTLA-4 may be considered as the first-line therapy for patients with hepatic MUP.

Digital Pathology Analysis Quantifies Spatial Heterogeneity of CD3, CD4, CD8, CD20, and FoxP3 Immune Markers in Triple-Negative Breast Cancer

Overwhelming evidence has shown the significant role of the tumor microenvironment (TME) in governing the triple-negative breast cancer (TNBC) progression. Digital pathology can provide key information about the spatial heterogeneity within the TME using image analysis and spatial statistics. These analyses have been applied to CD8+ T cells, but quantitative analyses of other important markers and their correlations are limited. In this study, a digital pathology computational workflow is formulated for characterizing the spatial distributions of five immune markers (CD3, CD4, CD8, CD20, and FoxP3) and then the functionality is tested on whole slide images from patients with TNBC. The workflow is initiated by digital image processing to extract and colocalize immune marker-labeled cells and then convert this information to point patterns. Afterward invasive front (IF), central tumor (CT), and normal tissue (N) are characterized. For each region, we examine the intra-tumoral heterogeneity. The workflow is then repeated for all specimens to capture inter-tumoral heterogeneity. In this study, both intra- and inter-tumoral heterogeneities are observed for all five markers across all specimens. Among all regions, IF tends to have higher densities of immune cells and overall larger variations in spatial model fitting parameters and higher density in cell clusters and hotspots compared to CT and N. Results suggest a distinct role of IF in the tumor immuno-architecture. Though the sample size is limited in the study, the computational workflow could be readily reproduced and scaled due to its automatic nature. Importantly, the value of the workflow also lies in its potential to be linked to treatment outcomes and identification of predictive biomarkers for responders/non-responders, and its application to parameterization and validation of computational immuno-oncology models.

Immunohistochemical Evaluation and Clinicopathological Correlation of Mer and Axl Tyrosine Kinase TAM Receptors in Cutaneous Melanoma

Background

Malignant melanoma (MM) is potentially the most dangerous form of skin tumor. In the last few years, the so-called TAM receptors, a unique family of tyrosine kinase (TK) receptors, have become increasingly important.

Objectives

To evaluate Mer and Axl TAM receptor expression to find clinicopathological features that could explain the biological behavior of MM.

Patients and Methods

Clinicopathological data were obtained from an MM electronic database at our Institute. We reviewed 24 cutaneous MM specimens. TAM receptor expression was assayed using immunohistochemistry. Combinative semiquantitative scoring was used for the evaluation of TAM receptor expression (MerTK and AxlTK). Appropriate statistical methods were used to evaluate a possible correlation between TAM receptor expression and the clinicopathological variables of the MM samples (univariate analysis and multivariate analysis).

Results

MerTK and AxlTK were expressed differently in the MM samples, with a major expression of the first receptor. The cells of the tumor microenvironment contributed to the majority of the total score. A significant association was found between AxlScore and the site of the tumor and between AxlScore and the variable ulceration; another correlation was found between MerScore and the following characteristics: pathological stage of the tumor (pT), sex, ulceration, and tumor-infiltrating lymphocytes.

Conclusions

All correlations between the expression of MerTK and AxlTK with the clinical and histological variables of MM should be validated in a large group of people in order to increase the validity and the impact of our observations, with subsequently therapeutic implications in the era of the "targeted therapy."

Gender Differences and Outcomes in Melanoma Patients

INTRODUCTION

Melanoma is one of the most common cancers in younger people. The incidence of cutaneous melanoma is increasing in patients of both sexes, with female patients generally living longer than their male counterparts. The aim of this retrospective study was to evaluate and confirm the sex-based difference in survival of melanoma patients and the relationship of this difference with pathological features.

METHODS

A total of 1023 patients who had been treated at the Department of Medical Oncology, Università Politecnica Marche (Ancona, Italy) and the INRCA-IRCCS Department of Dermatology (Ancona, Italy) between 1987 and 2014 were enrolled in the study.

RESULTS

In terms of stage of disease at onset, there was a significant difference in disease-free survival (DFS) and overall survival (OS) in favor of female patients in disease stage I (P  = 0.001 and P  = 0.01, respectively) and II (P  = 0.02 and P  = 0.009, respectively). Female patients also showed a significant improvement in 12-year DFS and 12-year OS adjusted for pathological features (Breslow thickness, ulceration, "absent" tumor-infiltrating lymphocyte (TIL) melanomas, "non-brisk" TIL pattern). Globally, female patients had an advantage over with male patients in both DFS and OS (P  < 0.001).

CONCLUSIONS

Our results show that women have a survival benefit over with men after adjustment for many variables that can reduce mortality risk in female melanoma patients. In a future investigation we wish to examine possible biological sex differences in tumor-host interactions.

Janus or Hydra: The Many Faces of T Helper Cells in the Human Tumour Microenvironment

CD4+ T helper (T_H) cells are key regulators in the tumour immune microenvironment (TIME), mediating the adaptive immunological response towards cancer, mainly through the activation of cytotoxic CD8+ T cells. After antigen recognition and proper co-stimulation, naïve T_H cells are activated, undergo clonal expansion, and release cytokines that will define the differentiation of a specific effector T_H cell subtype. These different subtypes have different functions, which can mediate both anti- and pro-tumour immunological responses. Here, we present the dual role of T_H cells restraining or promoting the tumour, the factors controlling their homing and differentiation in the TIME, their influence on immunotherapy, and their use as prognostic indicators.

Infiltrating and peripheral immune cell analysis in advanced gastric cancer according to the Lauren classification and its prognostic significance

BACKGROUND

The correlation between immune cells and the Lauren classification subtypes and their prognostic impact in advanced gastric cancer (AGC) are unknown.

METHODS

Circulating natural killer (NK) cells, CD4⁺ and CD8⁺ T cells, regulatory T cells (Tregs) and myeloid-derived suppressor cells (MDSCs) were quantified in peripheral blood mononuclear cells (PBMCs) from 67 patients with untreated AGC enrolled in the PRODIGE 17-ACCORD 20 trial. CD56⁺ cells (NK), CD8⁺, and FoxP3⁺ (Treg) tumor-infiltrating lymphocytes (TILs) were assessed in tumor samples.

RESULTS

Circulating NK and Treg proportions were significantly lower in patients with diffuse/mixed-type AGC (n = 27) than those with intestinal type (n = 40; median 6.3% vs 11.5%; p = 0.02 and median 3.3% vs 5.2%; p = 0.03, respectively). Proportions of circulating MDSC, CD4⁺ and CD8⁺ T cells were not associated with one pathological type. Among tumor-infiltrating cells, CD8⁺ T cells, but not NK or FoxP3⁺ cells, were significantly lower in diffuse/mixed-type AGC (median 21 vs 59 cells/field; p = 0.009). Patients with high circulating NK cell counts (> 17%) had a better overall survival than those with < 17% (HR 0.40; 95% CI [0.15-1.06]; p = 0.04). Patients with high CD8⁺ TIL counts (> 31 cells/field) had significantly longer overall survival (HR 0.44; 95% CI [0.21-0.92]; p = 0.02). The prognostic value of CD8⁺ TILs was maintained after adjustment for confounding factors, including the Lauren classification (HR = 0.42; 95% CI [0.18-0.96]; p = 0.039).

CONCLUSION

Diffuse/mixed-type AGC has lower rates of CD8⁺ TILs and circulating NK cells and Tregs than the intestinal type. This "cold tumor" phenotype may be associated with a worse outcome.

Immunotherapy of Cancer: Developments and Reference Points, an Unorthodox Approach

Oncology is currently a sector of medical science with accelerated progress due to rapid technological development, the advancement in molecular biology, and the invention of many innovative therapies. Immunotherapy partially accounts for this advance, since it is increasingly playing an important role in the treatment of cancer patients, bringing on a sense of hope and optimism through a series of clinical studies and cases with spectacular results. Immunotherapy, after the initial successes it experienced in the early 20th century, was forgotten after chemotherapy and radiotherapy prevailed and developed slowly in the background. Today, it is the new hope for cancer treatment, despite the unorthodox path it has followed. In this article, we study the course and key points of the discovery of immune-oncology from the oncologist's point of view. We also record the questions that have been posed about immunotherapy that sometimes lead to confusion or stalemate.

Tissue-Resident Memory T Cells in Cancer Immunosurveillance

Following their activation and expansion in response to foreign threats, many T cells are retained in peripheral tissues without recirculating in the blood. These tissue-resident CD8⁺ memory T (T_RM) cells patrol barrier surfaces and nonlymphoid organs, where their critical role in protecting against viral and bacterial infections is well established. Recent evidence suggests that T_RM cells also play a vital part in preventing the development and spread of solid tumors. Here, we discuss the emerging role of T_RM cells in anticancer immunity. We highlight defining features of tumor-localizing T_RM cells, examine the mechanisms through which they have recently been shown to suppress cancer growth, and explore their potential as future targets of cancer immunotherapy.

Targeting Mutated Plus Germline Epitopes Confers Pre-clinical Efficacy of an Instantly Formulated Cancer Nano-Vaccine

Personalized cancer vaccines hold promises for future cancer therapy. Targeting neoantigens is perceived as more beneficial compared to germline, non-mutated antigens. However, it is a practical challenge to identify and vaccinate patients with neoantigens. Here we asked whether two neoantigens are sufficient, and whether the addition of germline antigens would enhance the therapeutic efficacy. We developed and used a personalized cancer nano-vaccine platform based on virus-like particles loaded with toll-like receptor ligands. We generated three sets of multi-target vaccines (MTV) to immunize against the aggressive B16F10 murine melanoma: one set based on germline epitopes (GL-MTV) identified by immunopeptidomics, another set based on mutated epitopes (Mutated-MTV) predicted by whole exome sequencing and a last set combines both germline and mutated epitopes (Mix-MTV). Our results demonstrate that both germline and mutated epitopes induced protection but the best therapeutic effect was achieved with the combination of both. Our platform is based on Cu-free click chemistry used for peptide-VLP coupling, thus enabling bedside production of a personalized cancer vaccine, ready for clinical translation.

Inflammation: A key process in skin tumorigenesis

The extremely delicate shift from an inflammatory process to tumorigenesis is a field of major scientific interest. While the inflammation induced by environmental agents has well known underlying mechanisms, less is known concerning the oncogenic changes that follow an inflammatory chronic status in the tissue microenvironment that can lead to pro-tumorigenic processes. Regardless of the origin of the environmental factors, the maintenance of an inflammatory microenvironment is a clear condition that favors tumorigenesis. Inflammation sustains the proliferation and survival of malignant transformed cells, can promote angiogenesis and metastatic processes, can negatively regulate the antitumoral adaptive and innate immune responses and may alter the efficacy of therapeutic agents. There is an abundance of studies focusing on molecular pathways that trigger inflammation-mediated tumorigenesis, and these data have revealed a series of biomarkers that can improve the diagnosis and prognosis in oncology. In skin there is a clear connection between tissue destruction, inflammation and tumor onset. Inflammation is a self-limiting process in normal physiological conditions, while tumor is a constitutive process activating new pro-tumor mechanisms. Among skin cancers, the most commonly diagnosed skin cancers, squamous cell carcinoma and basal cell carcinoma (BCC) have important inflammatory components. The most aggressive skin cancer, melanoma, is extensively research in regards to the new context of novel developed immune-therapies. In skin cancers, inflammatory markers can find their place in the biomarker set for improvement of diagnosis and prognosis.

T cell receptor β-chain repertoire analysis of tumor-infiltrating lymphocytes in pancreatic cancer

Pancreatic cancer is lethal due to lack of perceptible symptoms and effective treatment methods. Immunotherapy may provide promising therapeutic choices for malignant tumors like pancreatic cancer. Tumor‐infiltrating lymphocytes (TIL) in tumor mesenchyme could recognize peptide antigens presented on the surface of tumor cells. The present study aimed to test the relationship between the T cell receptor (TCR) β repertoire of the tumor and peripheral blood, and also to investigate the intra‐tumor spatial heterogeneity of the TCR β repertoire in pancreatic cancer. To the best of our knowledge, this is the first study to evaluate the clonal composition of TCR β repertoire in TIL across the spatial extent of pancreatic cancer. In this study, we studied 5 patients who were diagnosed with primary pancreatic cancer. Ultra‐deep sequencing was used to assess the rearrangement of the TCR β‐chain (TCR β) gene. HE staining and immunohistochemistry of CD3, CD4, CD8 and HLA class I were used to show histopathology and immune conditions macroscopically. TIL repertoire showed that different regions of the same tumor showed a greater number of repertoire overlaps between each other than between peripheral blood, which suggested that T cell clones in pancreatic cancer might be quite different from those in peripheral blood. In contrast, intra‐tumoral TCR β repertoires were spatially homogeneous between different regions of a single tumor tissue. Based on these results, we speculated that the cellular adaptive immune response in pancreatic cancer was spatially homogeneous; this may pave the way for immunotherapy for the treatment of pancreatic cancer patients.

Melanoma of unknown primary

Formally described in the 1960s, melanoma of unknown primary (MUP) is characterized by the finding of metastatic melanoma within the lymph nodes, subcutaneous tissues, and other distant sites without an evident primary lesion. The most likely hypothesis of its etiology is an immune-mediated regression of the primary after metastasis has occurred. In addition, patients with MUP appear to have equivalent or better outcomes compared with patients with known primaries of a similar stage.

Hematopoietic stem cell specific V-ATPase controls breast cancer progression and metastasis via cytotoxic T cells

The interaction of recruited immune effector cells and cancer cells within tumor microenvironment (TME) shapes the fate of cancer progression and metastasis. Many cancers including breast cancer, express a specific vacuolar ATPase (a2V) on their cell surface which acidifies the extracellular milieu helping cancer cell proliferation and metastasis. To understand the role of immune cell-associated-a2V during breast tumor pathogenesis, we knocked-out a2V (KO) from the hematopoietic stem cells (HSC) and generated breast tumors in mice. The a2V-KO mice developed faster growing, larger, and metastatic breast tumors compared to control mice. Further investigation of the TME revealed a significant reduction in the presence of CD4⁺ and CD8⁺ T cells in the a2V-KO tumors. Targeted RNA-Seq of the cells of the TME demonstrated that pro-inflammatory cytokines, death receptors, death receptor ligands, and cytotoxic effectors were significantly down-regulated within the a2V-KO TME. Interestingly, analysis of immune cells in the blood, spleen, and thymus of the non-tumor bearing a2V-KO mice revealed a significant decrease in CD4⁺ and CD8⁺ T cell populations. For the first time, this study demonstrates that inhibition of V-ATPase expression in HSC leads to a decrease in CD4⁺ and CD8⁺ T cell populations and thus promotes breast tumor growth and metastasis.

Immune surveillance by autoreactive CD4-positive helper T cells is a common phenomenon in patients with acute myeloid leukemia

OBJECTIVES

The importance of autologous T-cell responses in immune surveillance against acute myeloid leukemia (AML) remains unclear. Therefore, we investigated the presence and functional reactivity of autoreactive T-cell responses against autologous AML blasts.

METHODS

T cells purified from PB samples harvested from patients during first complete remission were stimulated with autologous AML material harvested at diagnosis. After 12-14 days of coculture, the T cells were restimulated with autologous AML cells, and leukemia-reactive T-cell clones were isolated based on their expression of the activation marker CD137.

RESULTS

We demonstrated that AML-induced autoreactivity was predominantly mediated by CD4 T cells. These autoreactive T cells showed abundant cytokine production, coincided by modest cytotoxic activity. Upon coculture, the autoreactive T cells were able to increase the immunogenicity of the AML blasts. Interestingly, similar AML-directed reactivity was observed using HLA-identical responder T cells from healthy donors.

CONCLUSIONS

We demonstrated that the presence of AML-directed autoreactive T cells is a common phenomenon which appears to be part of the general T-cell repertoire also in healthy individuals. This autoreactive AML-directed T-cell response may directly contribute to anti-AML immune surveillance especially in the situation of minimal residual disease, but furthermore the immune-modulatory effect on the AML phenotype may pave the way for other immunological interventions.

Adenovirus Coding for Interleukin-2 and Tumor Necrosis Factor Alpha Replaces Lymphodepleting Chemotherapy in Adoptive T Cell Therapy

Lymphodepleting preconditioning with high-dose chemotherapy is commonly used to increase the clinical efficacy of adoptive T cell therapy (ACT) strategies, however, with severe toxicity for patients. Conversely, oncolytic adenoviruses are safe and, when engineered to express interleukin-2 (IL-2) and tumor necrosis factor alpha (TNF-α), they can achieve antitumor immunomodulatory effects similar to lymphodepletion. Therefore, we compare the safety and efficacy of such adenoviruses with a cyclophosphamide- and fludarabine-containing lymphodepleting regimen in the setting of ACT. Human adenovirus (Ad5/3-E2F-D24-hTNF-α-IRES-hIL-2; TILT-123) replication was studied using a Syrian hamster pancreatic tumor model (HapT1) infused with tumor-infiltrating lymphocytes (TILs). Using the oncolytic virus instead of lymphodepletion resulted in superior efficacy and survival. Immune cells responsive to TNF-α IL-2 were studied using an immunocompetent mouse melanoma model (B16.OVA) infused with ovalbumin-specific T (OT-I) cells. Here, the adenovirus approach improved tumor control together with increased intratumoral Th1 cytokine levels and infiltration of CD8+ T cells and CD86+ dendritic cells. Similar to humans, lymphodepleting preconditioning caused severe cytopenias, systemic inflammation, and damage to vital organs. Toxicity was minimal in adenovirus- and OT-I-treated mice. These findings demonstrate that ACT can be effectively facilitated by cytokine-coding adenovirus without requiring lymphodepletion, a rationale being clinically investigated.

Therapeutic cancer vaccine: building the future from lessons of the past

Anti-cancer vaccines have raised many hopes from the start of immunotherapy but have not yet been clinically successful. The few positive results of anti-cancer vaccines have been observed in clinical situations of low tumor burden or preneoplastic lesions. Several new concepts and new results reposition this therapeutic approach in the field of immunotherapy. Indeed, cancers that respond to anti-PD-1/PD-L1 (20-30%) are those that are infiltrated by anti-tumor T cells with an inflammatory infiltrate. However, 70% of cancers do not appear to have an anti-tumor immune reaction in the tumor microenvironment. To induce this anti-tumor immunity, therapeutic combinations between vaccines and anti-PD-1/PD-L1 are being evaluated. In addition, the identification of neoepitopes against which the immune system is less tolerated is giving rise to a new enthusiasm by the first clinical results of the vaccine including these neoepitopes in humans. The ability of anti-cancer vaccines to induce a population of anti-tumor T cells called memory resident T cells that play an important role in immunosurveillance is also a new criterion to consider in the design of therapeutic vaccines.

Phyto-polyphenols as potential inhibitors of breast cancer metastasis

Breast cancer is the most common cancer among women as metastasis is currently the main cause of mortality. Breast cancer cells undergoing metastasis acquire resistance to death signals and increase of cellular motility and invasiveness.Plants are rich in polyphenolic compounds, many of them with known medicinal effects. Various phyto-polyphenols have also been demonstrated to suppress cancer growth. Their mechanism of action is usually pleiotropic as they target multiple signaling pathways regulating key cellular processes such as proliferation, apoptosis and differentiation. Importantly, some phyto- polyphenols show low level of toxicity to untransformed cells, but selective suppressing effects on cancer cells proliferation and differentiation.In this review, we summarize the current information about the mechanism of action of some phyto-polyphenols that have demonstrated anti-carcinogenic activities in vitro and in vivo. Gained knowledge of how these natural polyphenolic compounds work can give us a clue for the development of novel anti-metastatic agents.

Stage IV melanoma of unknown primary: A population-based study in the United States from 1973 to 2014

BACKGROUND

Melanoma of unknown primary (MUP) is incompletely described on a population level.

OBJECTIVE

We sought to characterize stage IV MUP in a population-based cancer registry.

METHODS

We developed a novel search algorithm to identify cases of stage IV MUP in the Surveillance, Epidemiology, and End Results 18 registries from 1973 to 2014. Cases of stage IV melanoma of known primary (MKP) served as a comparison group. Age-standardized incidence rates, demographic characteristics, adjusted disease-specific survival, and Cox proportional hazard models were calculated for MUP and MKP.

RESULTS

A total of 322 stage IV MUP cases and 12,796 stage IV MKP cases were identified in Surveillance, Epidemiology, and End Results 18 registries from 1973 to 2014. The incidence of stage IV MUP is increasing, particularly for patients younger than 30 years of age. In multivariate analyses, age older than 50 and a lack of surgical treatment were negative prognostic factors for stage IV MUP. Relative survival, but not 5-year adjusted disease-specific survival, was higher for stage IV MUP than for MKP.

LIMITATIONS

Limitations include the retrospective study design and possible misclassification of MUP.

CONCLUSIONS

The incidence of stage IV MUP is increasing, and stage IV MUP shares similar prognostic factors with stage IV MKP, including age and surgical treatment.

Harnessing RNA sequencing for global, unbiased evaluation of two new adjuvants for dendritic-cell immunotherapy

Effective stimulation of immune cells is crucial for the success of cancer immunotherapies. Current approaches to evaluate the efficiency of stimuli are mainly defined by known flow cytometry-based cell activation or cell maturation markers. This method however does not give a complete overview of the achieved activation state and may leave important side effects unnoticed. Here, we used an unbiased RNA sequencing (RNA-seq)-based approach to compare the capacity of four clinical-grade dendritic cell (DC) activation stimuli used to prepare DC-vaccines composed of various types of DC subsets; the already clinically applied GM-CSF and Frühsommer meningoencephalitis (FSME) prophylactic vaccine and the novel clinical grade adjuvants protamine-RNA complexes (pRNA) and CpG-P. We found that GM-CSF and pRNA had similar effects on their target cells, whereas pRNA and CpG-P induced stronger type I interferon (IFN) expression than FSME. In general, the pathways most affected by all stimuli were related to immune activity and cell migration. GM-CSF stimulation, however, also induced a significant increase of genes related to nonsense-mediated decay, indicating a possible deleterious effect of this stimulus. Taken together, the two novel stimuli appear to be promising alternatives. Our study demonstrates how RNA-seq based investigation of changes in a large number of genes and gene groups can be exploited for fast and unbiased, global evaluation of clinical-grade stimuli, as opposed to the general limited evaluation of a pre-specified set of genes, by which one might miss important biological effects that are detrimental for vaccine efficacy.

T-lymphocyte homing: an underappreciated yet critical hurdle for successful cancer immunotherapy

Advances in cancer immunotherapy have offered new hope for patients with metastatic disease. This unfolding success story has been exemplified by a growing arsenal of novel immunotherapeutics, including blocking antibodies targeting immune checkpoint pathways, cancer vaccines, and adoptive cell therapy (ACT). Nonetheless, clinical benefit remains highly variable and patient-specific, in part, because all immunotherapeutic regimens vitally hinge on the capacity of endogenous and/or adoptively transferred T-effector (T_eff) cells, including chimeric antigen receptor (CAR) T cells, to home efficiently into tumor target tissue. Thus, defects intrinsic to the multi-step T-cell homing cascade have become an obvious, though significantly underappreciated contributor to immunotherapy resistance. Conspicuous have been low intralesional frequencies of tumor-infiltrating T-lymphocytes (TILs) below clinically beneficial threshold levels, and peripheral rather than deep lesional TIL infiltration. Therefore, a T_eff cell 'homing deficit' may arguably represent a dominant factor responsible for ineffective immunotherapeutic outcomes, as tumors resistant to immune-targeted killing thrive in such permissive, immune-vacuous microenvironments. Fortunately, emerging data is shedding light into the diverse mechanisms of immune escape by which tumors restrict T_eff cell trafficking and lesional penetrance. In this review, we scrutinize evolving knowledge on the molecular determinants of T_eff cell navigation into tumors. By integrating recently described, though sporadic information of pivotal adhesive and chemokine homing signatures within the tumor microenvironment with better established paradigms of T-cell trafficking under homeostatic or infectious disease scenarios, we seek to refine currently incomplete models of T_eff cell entry into tumor tissue. We further summarize how cancers thwart homing to escape immune-mediated destruction and raise awareness of the potential impact of immune checkpoint blockers on T_eff cell homing. Finally, we speculate on innovative therapeutic opportunities for augmenting T_eff cell homing capabilities to improve immunotherapy-based tumor eradication in cancer patients, with special focus on malignant melanoma.

Melanoma: tumor microenvironment and new treatments

In the recent past years, many discoveries in the tumor microenvironment have led to changes in the management of melanoma and it is rising up hopes, specially, to those in advanced stages. FDA approved seven new drugs from 2011 to 2014. They are: Vemurafenib, Dabrafenib and Trametinib, kinases inhibitors used for patients that have BRAFV600E mutation; Ipilimumab (anti-CTLA4), Pembrolizumab (anti-PD-1) and Nivolumab (anti-PD-1), monoclonal antibodies that stimulate the immune system; and Peginterferon alfa-2b, an anti-proliferative cytokine used as adjuvant therapy. In this article, we will review the molecular bases for these new metastatic melanoma therapeutic agents cited above and also analyze new molecular discoveries in melanoma study, as Cancer-Testis antigens (CT). They are capable of induce humoral and cellular immune responses in cancer patients and because of this immunogenicity and their restrict expression in normal tissues, they are considered an ideal candidate for vaccine development against cancer. Among CT antigens, NY-ESO-1 is the best characterized in terms of expression patterns and immunogenicity. It is expressed in 20-40% of all melanomas, more in metastatic lesions than in primary ones, and it is very heterogeneous inter and intratumoral. Breslow index is associate with NY-ESO-1 expression in primary cutaneous melanomas, but its relation to patient survival remains controversial.

Ret mouse very large tumors (VLTs) display altered ratios of infiltrating memory to naive T cells: Roles in tumor expansion

Melanoma is an aggressive skin cancer, however it is immunogenic. The size of the primary tumor is associated with the nodal metastases. Our goals were to characterize melanoma-associated antigens (MAAs) and tumor-infiltrating T-lymphocytes (TILs) subsets in the few very large tumors (VLTs) developing in ret transgenic mice of melanoma. Tumors >700mg (VLTs) were investigated for MAAs and subsets of TILs. Immunohistochemistry and flow cytometry-based studies were performed to determine the infiltration patterns of T-lymphocytes in VLTs. It was observed that zinc fixative restores the antigenicity of the cell-surface markers of lymphocyte subpopulations without the need of antigen retrieval, whereas formalin-based fixative fails to restore the antigenicity in the presence of antigen retrieval in the immunohistochemistry. VLTs from ret mice express MAAs, such as Tyrosinase, TRP-1, TRP-2 and gp-100. The mean±standard deviation (S.D.) T-cell infiltration per 400 times-high power field in VLTs; CD4(+) (2.33±1.3), CD8(+) (2.00±1.0), and CD4(+) Foxp3(+) (2.5±0.5) regulatory T cells infiltration was exclusively restricted to the tumor stroma. Moreover, our flow cytometry-based data reveal that % mean±S.D. naive CD3(+) CD4(+) T cell infiltration (32.8±4.0%) was significantly larger than effector (25.8±2.8%, p<0.01) and central memory cells (16.1±3.7%, p<0.001) in VLTs. Similarly, between CD3(+) CD8(+) T cells, naive cells infiltrate (57.7±2.3%) in a significantly larger frequency than effector (5.0±0.4%, p<0.0001) and central memory cell (4.8±1.7%, p<0.0001) subsets. These results suggest that the VLTs from ret mice display lowered infiltration ratios between memory and naive T cells, which could be associated with the relatively large growth of VLTs.

CD4+ and CD8+ T cells have opposing roles in breast cancer progression and outcome

The Cancer Immunoediting concept has provided critical insights suggesting dual functions of immune system during the cancer initiation and development. However, the dynamics and roles of CD4⁺ and CD8⁺ T cells in the pathogenesis of breast cancer remain unclear. Here we utilized two murine breast cancer models (4T1 and E0771) and demonstrated that both CD4⁺ and CD8⁺ T cells were increased and involved in immune responses, but with distinct dynamic trends in breast cancer development. In addition to cell number increases, CD4⁺ T cells changed their dominant subsets from Th1 in the early stages to Treg and Th17 cells in the late stages of the cancer progression. We also analyzed CD4⁺ and CD8⁺ T cell infiltration in primary breast cancer tissues from cancer patients. We observed that CD8⁺ T cells are the key effector cell population mediating effective anti-tumor immunity resulting in better clinical outcomes. In contrast, intra-tumoral CD4⁺ T cells have negative prognostic effects on breast cancer patient outcomes. These studies indicate that CD4⁺ and CD8⁺ T cells have opposing roles in breast cancer progression and outcomes, which provides new insights relevant for the development of effective cancer immunotherapeutic approaches.

Impaired gp100-Specific CD8(+) T-Cell Responses in the Presence of Myeloid-Derived Suppressor Cells in a Spontaneous Mouse Melanoma Model

Murine tumor models that closely reflect human diseases are important tools to investigate carcinogenesis and tumor immunity. The transgenic (tg) mouse strain tg(Grm1)EPv develops spontaneous melanoma due to ectopic overexpression of the metabotropic glutamate receptor 1 (Grm1) in melanocytes. In the present study, we characterized the immune status and functional properties of immune cells in tumor-bearing mice. Melanoma development was accompanied by a reduction in the percentages of CD4(+) T cells including regulatory T cells (Tregs) in CD45(+) leukocytes present in tumor tissue and draining lymph nodes (LNs). In contrast, the percentages of CD8(+) T cells were unchanged, and these cells showed an activated phenotype in tumor mice. Endogenous melanoma-associated antigen glycoprotein 100 (gp100)-specific CD8(+) T cells were not deleted during tumor development, as revealed by pentamer staining in the skin and draining LNs. They, however, were unresponsive to ex vivo gp100-peptide stimulation in late-stage tumor mice. Interestingly, immunosuppressive myeloid-derived suppressor cells (MDSCs) were recruited to tumor tissue with a preferential accumulation of granulocytic MDSC (grMDSCs) over monocytic MDSC (moMDSCs). Both subsets produced Arginase-1, inducible nitric oxide synthase (iNOS), and transforming growth factor-β and suppressed T-cell proliferation in vitro. In this work, we describe the immune status of a spontaneous melanoma mouse model that provides an interesting tool to develop future immunotherapeutical strategies.

Allo-reactive T cells for the treatment of hematological malignancies

Several mechanisms can be responsible for control of hematological tumors by allo-reactive T cells. Following allogeneic stem cell transplantation (alloSCT) donor T cells recognizing genetic disparities presented on recipient cells and not on donor cells are main effectors of tumor control, but also of the detrimental graft versus host disease (GVHD). Since after transplantation normal hematopoiesis is of donor origin, any T cell response directed against polymorphic antigens expressed on hematopoietic recipient cells but not on donor cells will result in an anti-tumor response not affecting normal hematopoiesis. After fully HLA-matched alloSCT, T cells recognizing polymorphic peptides derived from proteins encoded by genes selectively expressed in hematopoietic lineages may result in anti-tumor responses without GVHD. Due to the high susceptibility of hematopoietic cells for T cell recognition, a low amplitude of the overall T cell response may also be in favor of the anti-tumor reactivity in hematological malignancies. A mismatch between donor and patient for specific HLA-alleles can also be exploited to induce a selective T cell response against patient (malignant) hematopoietic cells. If restricting HLA class II molecules are selectively expressed on hematopoietic cells under non-inflammatory circumstances, allo HLA class-II responses may control the tumor with limited risk of GVHD. Alternatively, T cells recognizing hematopoiesis-restricted antigens presented in the context of mismatched HLA alleles may be used to treat patients with hematological cancers. This review discusses various ways to manipulate the allo-immune response aiming to exploit the powerful ability of allo-reactive T-cells to control the malignancies without causing severe damage to non-hematopoietic tissues.

Melanoma: oncogenic drivers and the immune system

Advances and in-depth understanding of the biology of melanoma over the past 30 years have contributed to a change in the consideration of melanoma as one of the most therapy-resistant malignancies. The finding that oncogenic BRAF mutations drive tumor growth in up to 50% of melanomas led to a molecular therapy revolution for unresectable and metastatic disease. Moving beyond BRAF, inactivation of immune regulatory checkpoints that limit T cell responses to melanoma has provided targets for cancer immunotherapy. In this review, we discuss the molecular biology of melanoma and we focus on the recent advances of molecularly targeted and immunotherapeutic approaches.

Parallel Expression of Enzyme Inhibitors of CD8T Cell Activity in Tumor Microenvironments and Secretory Endometrium

The divergent requirement for tolerance to support conception and protective response against sexually transmitted infections defines the unique immunological dynamics in the female reproductive tract (FRT). In part, these requirements are achieved by the cyclic modulation of cytolytic CD8T cell function in the FRT that underlie the respective immunosuppressive and immunocompetent milieus during the secretory and proliferative phases of the menstrual cycle. The CD8T cell function can be dampened by exposure to indoleamine 2,3-dioxygenase and/or arginase enzymes. Indeed, these 2 enzymes are known as primary inducers of immune suppression in tumor microenvironments. This review discusses the intriguing parallel expression of these 2 enzymes in tumor microenvironments and in the secretory endometrium. We surmise that investigating the underlying natural mechanisms that suppress and restore the immunocompetence of CD8T cells in the FRT each month may provide valuable insights into ways to artificially recapitulate these mechanisms and inhibit immune suppression in tumor microenvironments.

Characteristics of Tumor Infiltrating Lymphocyte and Circulating Lymphocyte Repertoires in Pancreatic Cancer by the Sequencing of T Cell Receptors

Pancreatic cancer has a poor prognosis and few effective treatments. The failure of treatment is partially due to the high heterogeneity of cancer cells within the tumor. T cells target and kill cancer cells by the specific recognition of cancer-associated antigens. In this study, T cells from primary tumor and blood of sixteen patients with pancreatic cancer were characterized by deep sequencing. T cells from blood of another eight healthy volunteers were also studied as controls. By analyzing the complementary determining region 3 (CDR3) gene sequence, we found no significant differences in the T cell receptor (TCR) repertoires between patients and healthy controls. Types and length of CDR3 were similar among groups. However, two clusters of patients were identified according to the degree of CDR3 overlap within tumor sample group. In addition, clonotypes with low frequencies were found in significantly higher numbers in primary pancreatic tumors compared to blood samples from patients and healthy controls. This study is the first to characterize the TCR repertoires of pancreatic cancers in both primary tumors and matched blood samples. The results imply that specific types of pancreatic cancer share potentially important immunological characteristics.

From T cell "exhaustion" to anti-cancer immunity

The immune system has the potential to protect from malignant diseases for extended periods of time. Unfortunately, spontaneous immune responses are often inefficient. Significant effort is required to develop reliable, broadly applicable immunotherapies for cancer patients. A major innovation was transplantation with hematopoietic stem cells from genetically distinct donors for patients with hematologic malignancies. In this setting, donor T cells induce long-term remission by keeping cancer cells in check through powerful allogeneic graft-versus-leukemia effects. More recently, a long awaited breakthrough for patients with solid tissue cancers was achieved, by means of therapeutic blockade of T cell inhibitory receptors. In untreated cancer patients, T cells are dysfunctional and remain in a state of T cell "exhaustion". Nonetheless, they often retain a high potential for successful defense against cancer, indicating that many T cells are not entirely and irreversibly exhausted but can be mobilized to become highly functional. Novel antibody therapies that block inhibitory receptors can lead to strong activation of anti-tumor T cells, mediating clinically significant anti-cancer immunity for many years. Here we review these new treatments and the current knowledge on tumor antigen-specific T cells.

Inflammation markers in cutaneous melanoma - edgy biomarkers for prognosis

There is a fine balance between inflammation and tumorigenesis. While environmentally induced inflammatory condition can precede a malignant transformation, in other cases an oncogenic change of unknown origin can induce an inflammatory microenvironment that promotes the development of tumors. Regardless of its origin, maintaining the inflammation milieu has many tumor-promoting effects. As a result, inflammation can aid the proliferation and survival of malignant cells, can promote angiogenesis and metastasis, can down-regulate innate/adaptive immune responses, and can alter responses to hormones and chemotherapeutic agents. There is an abundance of studies unveiling molecular pathways of cancer-related inflammation; this wealth of information brings new insights into biomarkers domain in the diagnosis and treatment improvement pursue. In cutaneous tissue there is an established link between tissue damage, inflammation, and cancer development. Inflammation is a self-limiting process in normal healthy physiological conditions, while tumorigenesis is a complex mechanism of constitutive pathway activation. Once more, in cutaneous melanoma, there is an unmet need for inflammatory biomarkers that could improve prognostication. Targeting inflammation and coping with the phenotypic plasticity of melanoma cells represent rational strategies to specifically interfere with metastatic progression. We have shown that there is a prototype of intratumor inflammatory infiltrate depicting a good prognosis, infiltrate that is composed of numerous T cells CD3+, Langerhans cells, few/absent B cells CD20+ and few/absent plasma cells. Circulating immune cells characterized by phenotype particularities are delicately linked to the stage melanoma is diagnosed in. Hence circulatory immune sub-populations, with activated or suppressor phenotype would give the physician a more detailed immune status of the patient. A panel of tissue/circulatory immune markers can complete the immune status, can add value to the overall prognostic of the patient and, as a result direct/redirect the therapy choice. The future lies within establishing low-cost, affordable/available, easily reproducible assays that will complete the pre-clinical parameters of the patient.

Role of radiation therapy as immune activator in the era of modern immunotherapy for metastatic malignant melanoma

Metastatic melanoma is difficult to treat, and often portends a grim prognosis. For patients with cerebral metastases, the prognosis is even more dire. Systemic immunotherapy and targeted agents are emerging as the mainstay of treatment for metastatic melanoma. Although immunotherapy has been shown to prolong relapse-free survival and long-term control of micrometastatic disease, the response rate is suboptimal, prompting the need to optimize and improve therapy. Accumulating evidence suggests that in addition to effective locoregional control, radiation therapy (RT) may induce immune activation and expansion of T lymphocytes recognizing melanocyte-specific antigens including activated cytotoxic T lymphocytes that can potentially kill melanoma cells. In some cases, RT contributes to the clearance of metastatic disease in distant, nonirradiated regions, a bystander phenomenon called the abscopal effect. Here, we evaluate the potential promise of ablative radiation treatment in the era of modern immunotherapy by presenting a patient with metastatic melanoma who remained disease free for over 3 years after an initial diagnosis of advanced metastatic melanoma with brain, subcutaneous tissue, mesenteric, pelvic, and retroperitoneal involvement. The patient failed initial stereotactic radiosurgery, but responded to whole-brain RT in combination with interleukin-2 immunotherapy. Thus, combination RT with immunotherapy may be synergistic by promoting the release and processing of melanoma antigens that can be presented by dendritic cells. This in turn may augment the response to therapies that center on expansion and/or activation of antitumor T cells.

Tumor lysate-loaded biodegradable microparticles as cancer vaccines

Cancer vaccines that use tumor lysate (TL) as a source of tumor-associated antigens (TAAs) have significant potential for generating therapeutic anti-tumor immune responses. Vaccines encompassing TL bypass the limitations of single antigen vaccines by simultaneously stimulating immunity against multiple TAAs, thereby broadening the repertoire of TAA-specific T-cell clones available for activation. Administration of TL in particulate form, such as when encapsulated in biodegradable microparticles, increases its immunostimulatory capacity and produces more robust immune responses than when TL is given in soluble form. These effects can be further enhanced by co-administering TL with adjuvants. A number of recent studies using polymeric microparticle delivery of TL, with or without adjuvants, have produced promising results in preclinical studies. In this review, we will discuss current experimental approaches involving TL being pursued in the oncoimmunology field, and comment on strategies such as combining specific chemotherapeutic agents with TL microparticle delivery that may eventually lead to improved survival outcomes for cancer patients.

Paradigm Shift in Dendritic Cell-Based Immunotherapy: From in vitro Generated Monocyte-Derived DCs to Naturally Circulating DC Subsets

Dendritic cell (DC)-based immunotherapy employs the patients’ immune system to fight neoplastic lesions spread over the entire body. This makes it an important therapy option for patients suffering from metastatic melanoma, which is often resistant to chemotherapy. However, conventional cellular vaccination approaches, based on monocyte-derived DCs (moDCs), only achieved modest response rates despite continued optimization of various vaccination parameters. In addition, the generation of moDCs requires extensive ex vivo culturing conceivably hampering the immunogenicity of the vaccine. Recent studies, thus, focused on vaccines that make use of primary DCs. Though rare in the blood, these naturally circulating DCs can be readily isolated and activated thereby circumventing lengthy ex vivo culture periods. The first clinical trials not only showed increased survival rates but also the induction of diversified anti-cancer immune responses. Upcoming treatment paradigms aim to include several primary DC subsets in a single vaccine as pre-clinical studies identified synergistic effects between various antigen-presenting cells.

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.

The emerging role of immunosurveillance in dictating metastatic spread in breast cancer

It is now well known that the immune system can recognize transformed cells and control the initiation and growth of some cancers, a process termed tumor immunosurveillance. Key regulators of this process have been described in the primary tumor setting, where the balance of protumor and antitumor responses dictates tumor initiation and progression. Accumulating evidence suggests that immunosurveillance may also be critical for regulating metastatic spread, the most fatal aspect of cancer, and that mechanisms of overcoming immune control may be quite different from those at the primary site. Our recent findings support loss of type I interferon (IFN) signaling as a tumor-cell intrinsic mechanism of evading metastasis-specific immune responses in breast cancer. We revealed that type I IFN-induced innate (natural killer) and adaptive (CD8(+) T cell) responses suppressed bone metastatic growth and this was associated with decreased accumulation of immune suppressor cells (myeloid-derived suppressor cells). This review summarizes recent findings that are in support of tumor-induced immunosurveillance in regulating metastatic spread, including evidence that immune regulation of primary tumors may be distinct from those dictating metastasis.

Immune parameters in the prognosis and therapy monitoring of cutaneous melanoma patients: experience, role, and limitations

Cutaneous melanoma is an immune-dependent aggressive tumour. Up to our knowledge, there are no reports regarding immune parameters monitoring in longitudinal followup of melanoma patients. We report a followup for 36 months of the immune parameters of patients diagnosed in stages I-IV. The circulatory immune parameters comprised presurgery and postsurgery immune circulating peripheral cells and circulating intercommunicating cytokines. Based on our analysis, the prototype of the intratumor inflammatory infiltrate in a melanoma with good prognosis is composed of numerous T cells CD3+, few or even absent B cells CD20+, few or absent plasma cells CD138+, and present Langerhans cells CD1a+ or langerin+. Regarding circulatory immune cells, a marker that correlates with stage is CD4+/CD8+ ratio, and its decrease clearly indicates a worse prognosis of the disease. Moreover, even in advanced stages, patients that have an increased overall survival rate prove the increase of this ratio. The decrease in the circulating B lymphocytes with stage is balanced by an increase in circulating NK cells, a phenomenon observed in stage III. Out of all the tested cytokines in the followup, IL-6 level correlated with the patient's survival, while in our study, IL-8, IL-10, and IL-12 did not correlate statistically in a significant way with overall survival, or relapse-free survival.

Immune alterations in malignant melanoma and current immunotherapy concepts

INTRODUCTION

Malignant melanoma is a highly aggressive, immunogenic tumor that has the ability to modulate the immune system to its own advantage. Patients with melanoma present numerous cellular immune defects and cytokine abnormalities, all leading to suppression of the host anti-tumor immune response. Innovative treatment strategies can be achieved through employing our knowledge of the melanoma-induced immune alterations.

AREAS COVERED

The authors review comprehensively the immune abnormalities in individuals with melanoma, and provide a summary of currently available melanoma immunotherapy agents that are currently on the market or undergoing clinical trials.

EXPERT OPINION

Ipilimumab, a monoclonal antibody directed against the CTLA-4, is one of the current forefront treatment strategies in malignant melanoma. Novel immunomodulating agents have shown clear activity in patients with malignant melanoma. These include anti-PD-1 and anti-PD-1 ligand antibodies that may soon become important items in the anti-melanoma armamentarium. Combinations of different immunotherapy agents, between themselves or with other agents, are currently being studied in an attempt to further enhance the antineoplastic effect in patients with malignant melanoma.

Vaccines against advanced melanoma

Research shows that cancers are recognized by the immune system but that the immune recognition of tumors does not uniformly result in tumor rejection or regression. Quantitating the success or failure of the immune system in tumor elimination is difficult because we do not really know the total numbers of encounters of the immune system with the tumors. Regardless of that important issue, recognition of the tumor by the immune system implicitly contains the idea of the tumor antigen, which is what is actually recognized. We review the molecular identity of all forms of tumor antigens (antigens with specific mutations, cancer-testis antigens, differentiation antigens, over-expressed antigens) and discuss the use of these multiple forms of antigens in experimental immunotherapy of mouse and human melanoma. These efforts have been uniformly unsuccessful; however, the approaches that have not worked or have somewhat worked have been the source of many new insights into melanoma immunology. From a critical review of the various approaches to vaccine therapy we conclude that individual cancer-specific mutations are truly the only sources of cancer-specific antigens, and therefore, the most attractive targets for immunotherapy.