Principles of Immunotherapy in Melanoma

Organ-specific accuracy of [18F]FDG-PET/CT in identifying immune-related adverse events in patients with high-risk melanoma treated with adjuvant immune checkpoint inhibitor

PURPOSE

This study aimed to determine the organ-specific accuracy of [18F]FDG-PET/CT in identifying immune-related adverse events (irAEs) in patients with high-risk (stage III/IV) surgically resected melanoma treated with an adjuvant immune checkpoint inhibitor (ICI) and determine the incidence of irAEs within the first year after starting treatment.

MATERIALS AND METHODS

This registry-based study included individuals who had undergone surgical removal of melanoma and were undergoing adjuvant ICI treatment (either nivolumab or pembrolizumab). The study specifically enrolled patients who had undergone both a baseline and at least one subsequent follow-up [18F]FDG-PET/CT scan. Follow-up scans were performed every third month in the first year after surgery to screen for disease recurrence. We retrospectively compared the follow-up scans with baseline scans to identify irAEs. Clinical information on irAEs was obtained from medical records and served as a reference standard for determining the accuracy of [18F]FDG-PET/CT.

RESULTS

A total of 123 patients with 363 [18F]FDG-PET/CT scans were included, and 65 patients (52.8%) developed irAEs. In decreasing order, the organ-specific incidences of irAEs were: skin 26/65 (40%), muscle and joints 21/65 (32.3%), intestines 13/65 (20%), thyroid gland 12/65 (18.5%), lungs 4/65 (6.2%), and heart 2/65 (3.1%). The sensitivities and specificities of [18F]FDG-PET/CT for diagnosing irAEs were: skin 19% (95% CI: 7-39%) and 95% (88-98%), muscles and joints 71% (48-89%) and 83% (75-90%), intestines 100% (75-100%) and 85% (77-91%); thyroid gland 92% (62-99%) and 95% (89-98%), lungs 75% (19-99%) and 90% (83-95%), and heart 50% (13-99%) and 97% (92-99%), respectively.

CONCLUSION

[18F]FDG-PET/CT generally had moderate to high sensitivities (except for skin and heart) and specificities in diagnosing irAEs in patients receiving adjuvant ICI; this could be suggested to be systematically assessed and reported in scan reports.

Metformin improved a heterologous prime-boost of dual-targeting cancer vaccines to inhibit tumor growth in a melanoma mouse model

Therapeutic cancer vaccines, which induce anti-tumor immunity by targeting specific antigens, constitute a promising approach to cancer therapy. Our previous work proposed an optimized heterologous immunization strategy using cancer gene vaccines co-targeting MUC1 and survivin. Administration of a DNA vaccine three times within a week followed by a single recombinant MVA (rMVA) boost was able to efficiently induce anti-tumor immunity and inhibit tumor growth in tumor-bearing mouse models However, the complex immunosuppressive tumor microenvironment always limits infiltration by vaccine-induced T cells. Modifying the immunosuppressive microenvironment of tumors would be a breakthrough in enhancing the therapeutic effects of a cancer vaccine. Recent studies have reported that metformin, a type 2 diabetes drug, may ameliorate the tumor microenvironment, thereby enhancing anti-tumor immunity. Here, we tested whether the combinational therapeutic strategy of cancer vaccines administered with a heterologous prime-boost strategy with metformin enhanced anti-tumor effects in a melanoma mouse model. The results showed that metformin promoted the transition of M2-tumor-associated macrophages (M2-TAM) to M1-TAM, induced more tumor-infiltrating proliferative CD4 and CD8 T cells, and decreased exhausted T cells. This combinational treatment induced anti-tumor immunity from cancer vaccines, ameliorating the tumor microenvironment, showing improved tumor inhibition, and prolonging survival in tumor-bearing mice compared with either a cancer vaccine or metformin alone.

Predictive value and accuracy of [18F]FDG PET/CT modified response criteria for checkpoint immunotherapy in patients with advanced melanoma

PURPOSE

Immune checkpoint inhibitors (ICIs) are widely used in metastatic melanoma and dramatically alter the treatment of these patients. Given the high cost and potential toxicity, a reliable method for evaluating treatment response is needed. In this study, we assessed tumor response in patients with metastatic melanoma treated with ICIs using three modified response criteria: PET Response Evaluation Criteria for Immunotherapy (PERCIMT), PET Response Criteria in Solid Tumors for up to Five Lesions (PERCIST5), and immunotherapy-modified PET Response Criteria in Solid Tumors for up to Five Lesions (imPERCIST5).

METHODS

Ninety-one patients with non-resectable stage IV metastatic melanoma who received ICIs were retrospectively enrolled in this study. Each patient had two [18F]FDG PET/CT scans performed before and after ICI therapy. Responses at the follow-up scan were evaluated according to PERCIMT, PERCIST5, and imPERCIST5 criteria. Patients were classified into four groups: complete metabolic response (CMR), partial metabolic response (PMR), progressive metabolic disease (PMD), and stable metabolic disease (SMD). To assess the "disease control rate," two groups have been defined based on each criterion: patients with CMR, PMR, and SMD as "disease-controlled group (i.e., responders)" and PMD as the "uncontrolled-disease group (i.e., non-responders)". The correspondence between metabolic tumor response defined by these criteria and clinical outcome was assessed and compared.

RESULTS

The response and the disease control rates were 40.7% and 71.4%, 41.8% and 50.5%, and 54.9% and 74.7% based on the PERCIMT, PERCIST5, and imPERCIST5 criteria, respectively. PERCIMT and imPERCIST5 showed significantly different disease control rates from that of PERCIST5 (P < 0.001), whereas it was not significant between PERCIMT and imPERCIST5. Overall survival was significantly longer in the metabolic responder groups than in the non-responder groups based on PERCIMT and PERCIST5 criteria (PERCIMT: 2.48 versus 1.47 years, P = 0.003; PERCIST5: 2.57 versus 1.81 years. P = 0.017). However, according to imPERCIST5 criterion, this difference was not observed (P = 0.12).

CONCLUSION

Although the appearance of new lesions can be secondary to an inflammatory response to ICIs and indicative of pseudoprogression, given the higher rate of true progression, the appearance of new lesions should be interpreted deliberately. Of the three assessed modified criteria, PERCIMT appear to provide more reliable metabolic response assessment that correlates strongly with overall patient survival.

A comprehensive review on novel targeted therapy methods and nanotechnology-based gene delivery systems in melanoma

Melanoma, a malignant form of skin cancer, has been swiftly increasing in recent years. Although there have been significant advancements in clinical treatment underlying a well-understanding of melanoma-susceptible genes and the molecular basis of melanoma pathogenesis, the permanency of response to therapy is frequently constrained by the emergence of acquired resistance and systemic toxicity. Conventional therapies, including surgical resection, chemotherapy, radiotherapy, and immunotherapy, have already been used to treat melanoma and are dependent on the cancer stage. Nevertheless, ineffective side effects and the heterogeneity of tumors pose major obstacles to the therapeutic treatment of malignant melanoma through such strategies. In light of this, advanced therapies including nucleic acid therapies (ncRNA, aptamers), suicide gene therapies, and gene therapy using tumor suppressor genes, have lately gained immense attention in the field of cancer treatment. Furthermore, nanomedicine and targeted therapy based on gene editing tools have been applied to the treatment of melanoma as potential cancer treatment approaches nowadays. Indeed, nanovectors enable delivery of the therapeutic agents into the tumor sites by passive or active targeting, improving therapeutic efficiency and minimizing adverse effects. Accordingly, in this review, we summarized the recent findings related to novel targeted therapy methods as well as nanotechnology-based gene systems in melanoma. We also discussed current issues along with potential directions for future research, paving the way for the next-generation of melanoma treatments.

Checkpoint Inhibitor-Induced Colitis: An Update

Immunotherapy with immune checkpoint inhibitors (ICIs) nowadays has indications for several solid tumors. The current targets for ICIs are CTLA-4, PD-1, and PD-L1 receptors. Despite the clinical advantages derived from ICIs, a variety of side effects are linked to overstimulation of the immune system. Among these, ICI-related colitis is one of the most common, with a disabling impact on the patient. Diarrhea, abdominal pain, abdominal distension, cramping, and hematochezia are the most common ICI enterocolitis presenting symptoms. The most frequently used grading system for assessment of the severity of ICI enterocolitis is called the Common Terminology Criteria for Adverse Events (CTCAE) grading. With regard to the histological picture, there is no specific feature; however, microscopic damage can be classified into five types: (1) acute active colitis, (2) chronic active colitis, (3) microscopic colitis-like, (4) graft-versus-host disease-like, and (5) other types. Supportive therapy (oral hydration, a bland diet without lactose or caffeine, and anti-diarrheal agents) is indicated in mild colitis. Symptomatic treatment alone or with loperamide, a low-fiber diet, and spasmolytics are recommended for low-grade diarrhea. In more severe cases, corticosteroid treatment is mandatory. In refractory cases, off-label use of biological therapies (infliximab or vedolizumab) was proposed.

Clinical and molecular overview of immunotherapeutic approaches for malignant skin melanoma: Past, present and future

Traditional therapeutic approaches for malignant melanoma, have proved to be limited and/or ineffective, especially with respect to their role in improving patient survival and tumor recurrence. In this regard, immunotherapy has been demonstrated to be a promising therapeutic alternative, boosting antitumor responses through the modulation of cell signaling pathways involved in the effector mechanisms of the immune system, particularly, the so-called "immunological checkpoints". Clinical studies on the efficacy and safety of immunotherapeutic regimens, alone or in combination with other antitumor approaches, have increased dramatically in recent decades, with very encouraging results. Hence, this review will discuss the current immunotherapeutic regimens used to treat malignant melanoma, as well as the molecular and cellular mechanisms involved. In addition, current clinical studies that have investigated the use, efficacy, and adverse events of immunotherapy in melanoma will also be discussed.

Melanoma Management: From Epidemiology to Treatment and Latest Advances

Simple Summary

Melanoma is a major public health issue that claims the lives of thousands of people every year. Furthermore, the outlook for the coming years is not encouraging with increasing morbidity and mortality trends. This review aims to offer an updated overview of various aspects related to cutaneous melanoma, from epidemiology, etiology, clinical presentation, prevention, diagnosis and staging. Moreover, conventional treatments currently available as well as the latest advances in clinical trials regarding new drugs and/or combinations, including nanotechnology-based strategies are also reviewed.

Abstract

Melanoma is the deadliest skin cancer, whose morbidity and mortality indicators show an increasing trend worldwide. In addition to its great heterogeneity, melanoma has a high metastatic potential, resulting in very limited response to therapies currently available, which were restricted to surgery, radiotherapy and chemotherapy for many years. Advances in knowledge about the pathophysiological mechanisms of the disease have allowed the development of new therapeutic classes, such as immune checkpoint and small molecule kinase inhibitors. However, despite the incontestable progress in the quality of life and survival rates of the patients, effectiveness is still far from desired. Some adverse side effects and resistance mechanisms are the main barriers. Thus, the search for better options has resulted in many clinical trials that are now investigating new drugs and/or combinations. The low water solubility of drugs, low stability and rapid metabolism limit the clinical potential and therapeutic use of some compounds. Thus, the research of nanotechnology-based strategies is being explored as the basis for the broad application of different types of nanosystems in the treatment of melanoma. Future development focus on challenges understanding the mechanisms that make these nanosystems more effective.

Immuno-Imaging (PET/SPECT)-Quo Vadis?

The use of immunotherapy has revolutionized the treatment regimen of certain cancer types, but response assessment has become a difficult task with conventional methods such as CT/MRT or FDG PET-CT and the classical response criteria such as RECIST or PERCIST which have been developed for chemotherapeutic treatment. Plenty of new tracers have been published to improve the assessment of treatment response and to stratify the patient population. We gathered the information on published tracers (in total, 106 individual SPECT/PET tracers were identified) and performed a descriptor-based analysis; in this way, we classify the tracers with regard to target choice, developability (probability to progress from preclinical stage into the clinic), translatability (probability to be widely applied in the 'real world'), and (assumed) diagnostic quality. In our analysis, we show that most tracers are targeting PD-L1, PD-1, CTLA-4, and CD8 receptors by using antibodies or their fragments. Another finding is that plenty of tracers possess only minor iterations regarding chelators and nuclides instead of approaching the problem in a new innovative way. Based on the data, we suggest an orthogonal approach by targeting intracellular targets with PET-activatable small molecules that are currently underrepresented.

Mechanisms of Immunotherapy Resistance in Cutaneous Melanoma: Recognizing a Shapeshifter

Melanoma is one of the seven most common cancers in the United States, and its incidence is still increasing. Since 2011, developments in targeted therapies and immunotherapies have been essential for significantly improving overall survival rates. Prior to the advent of targeted and immunotherapies, metastatic melanoma was considered a death sentence, with less than 5% of patients surviving more than 5 years. With the implementation of immunotherapies, approximately half of patients with metastatic melanoma now survive more than 5 years. Unfortunately, this also means that half of the patients with melanoma do not respond to current therapies and live less than 5 years after diagnosis. One major factor that contributes to lower response in this population is acquired or primary resistance to immunotherapies via tumor immune evasion. To improve the overall survival of melanoma patients new treatment strategies must be designed to minimize the risk of acquired resistance and overcome existing primary resistance. In recent years, many advances have been made in identifying and understanding the pathways that contribute to tumor immune evasion throughout the course of immunotherapy treatment. In addition, results from clinical trials focusing on treating patients with immunotherapy-resistant melanoma have reported some initial findings. In this review, we summarize important mechanisms that drive resistance to immunotherapies in patients with cutaneous melanoma. We have focused on tumor intrinsic characteristics of resistance, altered immune function, and systemic factors that contribute to immunotherapy resistance in melanoma. Exploring these pathways will hopefully yield novel strategies to prevent acquired resistance and overcome existing resistance to immunotherapy treatment in patients with cutaneous melanoma.

Melanoma and Nanotechnology-Based Treatment

Melanoma is a malignant tumor arising in melanocytes from the basal layer of the epidermis and is the fifth most commonly diagnosed cancer in the United States. Melanoma is aggressive and easily metastasizes, and the survival rate is low. Nanotechnology-based diagnosis and treatment of melanoma have attracted increasing attention. Importantly, nano drug delivery systems have the advantages of increasing drug solubility, enhancing drug stability, prolonging half-life, optimizing bioavailability, targeting tumors, and minimizing side effects; thus, these systems can facilitate tumor cytotoxicity to achieve effective treatment of melanoma. In this review, we discuss current nanosystems used in the diagnosis and treatment of melanoma, including lipid systems, inorganic nanoparticles, polymeric systems, and natural nanosystems. The excellent characteristics of novel and effective drug delivery systems provide a basis for the broad applications of these systems in the diagnosis and treatment of melanoma, particularly metastatic melanoma.

Identification of Novel Molecular Therapeutic Targets and Their Potential Prognostic Biomarkers Based on Cytolytic Activity in Skin Cutaneous Melanoma

Skin cutaneous melanoma (SKCM) attracts attention worldwide for its extremely high malignancy. A novel term cytolytic activity (CYT) has been introduced as a potential immunotherapy biomarker associated with counter-regulatory immune responses and enhanced prognosis in tumors. In this study, we extracted all datasets of SKCM patients, namely, RNA sequencing data and clinical information from The Cancer Genome Atlas (TCGA) database and the Gene Expression Omnibus (GEO) database, conducted differential expression analysis to yield 864 differentially expressed genes (DEGs) characteristic of CYT and used non-negative matrix factorization (NMF) method to classify molecular subtypes of SKCM patients. Among all genes, 14 hub genes closely related to prognosis for SKCM were finally screen out. Based on these genes, we constructed a 14-gene prognostic risk model and its robustness and strong predictive performance were further validated. Subsequently, the underlying mechanisms in tumor pathogenesis and prognosis have been defined from a number of perspectives, namely, tumor mutation burden (TMB), copy number variation (CNV), tumor microenvironment (TME), infiltrating immune cells, gene set enrichment analysis (GSEA) and immune checkpoint inhibitors (ICIs). Furthermore, combined with GTEx database and HPA database, the expression of genes in the model was verified at the transcriptional level and protein level, and the relative importance of genes in the model was described by random forest algorithm. In addition, the model was used to predict the difference in sensitivity of SKCM patients to chemotherapy and immunotherapy. Finally, a nomogram was constructed to better aid clinical diagnosis.

ZC3H15 Correlates with a Poor Prognosis and Tumor Progression in Melanoma

Zinc figure CCCH-type containing 15 (ZC3H15), also called developmentally regulated GTP-binding protein 1 (DRG1) family regulatory protein 1 (DFRP1), is a zinc finger containing protein. Despite playing a role in cellular signaling, it is found overexpressed in acute myeloid leukemia and also an independent prognostic marker in hepatocellular carcinoma patients. However, the biological effect of ZC3H15 in malignant melanoma (MM) remains unexplored. The expression of ZC3H15 in patients was analyzed using the R2: Genomics Analysis and Visualization Platform database. Immunohistochemical analysis, western blot, and qRT-PCR were used to detect ZC3H15 expression in melanoma tissues and cell lines. MTT, BrdU, flow cytometry assay, transwell, and western blot were performed to explore the proliferation, cell cycle, invasion, and migration of melanoma cells. We undertaken colony formation assay in vitro and tumor xenograft in vivo to detect the tumorigenicity of melanoma cells. In the present study, ZC3H15 was demonstrated highly expressed in melanoma tissues and cells. Elevated ZC3H15 impairs the survival of melanoma patients. Meanwhile, attenuation of ZC3H15 in melanoma cells inhibited cell proliferation and induced cycle arrest at G0/G1 phase. Consistently, the expression of cell cycle-related proteins cyclin dependent kinase 4 (CDK4), CDK6, and cyclin D1 (CCND1) was decreased while p21 was upregulated. Furthermore, we found the migration and invasion abilities were inhibited in ZC3H15-knockdown melanoma cells. In addition, downregulation of ZC3H15 resulted in inhibition of colony formation abilities in vitro and tumorigenesis in vivo. ZC3H15 promotes proliferation, migration/invasion, and tumorigenicity of melanoma cells. As a promising biomarker and therapeutic target in MM, ZC3H15 is worthy of further exploration.

Response criteria for immunotherapy and the radiologic patterns of immune-related adverse events

Immunotherapy has revolutionized clinical outcomes in both early-stage and advanced-stage malignancies. Immunotherapy has improved patient survival in both solid and hematologic disorders with the potential added benefit of less toxicity compared to conventional cytotoxic chemotherapy. Imaging plays a fundamental role in monitoring treatment response and assessment of immune-related adverse events, e.g. pneumonitis, colitis, etc. Familiarity with the current strategies of immune-related response evaluation and their limitations is essential for radiologists to guide clinicians with their treatment decisions. Radiologists should be aware of the wide spectrum of immune-related adverse events and their various radiological features as well as the patterns of treatment response associated with immunotherapies.

Chemotherapeutic drug-induced immunogenic cell death for nanomedicine-based cancer chemo-immunotherapy

Chemotherapy has been a conventional paradigm for cancer treatment, and multifarious chemotherapeutic drugs have been widely employed for decades with significant performances in suppressing tumors. Moreover, some of the antitumor chemotherapeutic agents, such as doxorubicin (DOX), oxaliplatin (OXA), cyclophosphamide (CPA) and paclitaxel (PTX), can also tackle tumors through the induction of immunogenic cell death (ICD) in tumor cells to trigger specific antitumor immune responses of the body and improve chemotherapy efficacy. In recent years, chemo-immunotherapy has attracted increasing attention as one of the most promising combination therapies to struggle with malignant tumors. Many effective antitumor therapies have benefited from the successful induction of ICD in tumors, which could incur the release of endogenous danger signals and tumor-associated antigens (TAAs), further stimulating antigen-presenting cells (APCs) and ultimately initiating efficient antitumor immunity. In this review, several well-characterized damage-associated molecular patterns (DAMPs) were introduced and the progress of ICD induced by representative chemotherapeutic drugs for nanomedicine-based chemo-immunotherapy was highlighted. In addition, the combination strategies involving ICD cooperated with other therapies were discussed. Finally, we shared some perspectives in chemotherapeutic drug-induced ICD for future chemo-immunotherapy. It was hoped that this review would provide worthwhile presentations and enlightenments for cancer chemo-immunotherapy.

Phase II study of ceralasertib (AZD6738) in combination with durvalumab in patients with advanced/metastatic melanoma who have failed prior anti-PD-1 therapy

BACKGROUND

Modulating the DNA damage response and repair (DDR) pathways is a promising strategy for boosting cancer immunotherapy. Ceralasertib (AZD6738) is an oral inhibitor of the serine/threonine protein kinase ataxia telangiectasia and Rad3-related protein, which is crucial for DDR.

PATIENTS AND METHODS

This phase II trial evaluated ceralasertib plus durvalumab for the treatment of patients with metastatic melanoma who had failed anti-programmed cell death protein 1 therapy.

RESULTS

Among the 30 patients, we observed an overall response rate of 31.0% and a disease control rate of 63.3%. Responses were evident across patients with acral, mucosal, and cutaneous melanoma. The median duration of response was 8.8 months (range, 3.8-11.7 months). The median progression-free survival was 7.1 months (95% confidence interval, 3.6-10.6 months), and the median overall survival was 14.2 months (95% confidence interval, 9.3-19.1 months). Common adverse events were largely hematologic and manageable with dose interruptions and reductions. Exploratory biomarker analysis suggested that tumors with an immune-enriched microenvironment or alterations in the DDR pathway were more likely to respond to the study treatment.

CONCLUSION

We conclude that ceralasertib in combination with durvalumab has promising antitumor activity among patients with metastatic melanoma who have failed anti-programmed cell death protein 1 therapy, and constitute a population with unmet needs.

Using Immune-Related lncRNA Signature for Prognosis and Response to Immunotherapy in Cutaneous Melanoma

Background

Cutaneous melanoma is a highly malignant skin tumor, and most patients have a poor prognosis. In recent years, immunotherapy has assumed an important role in the treatment of advanced cutaneous melanoma, but only a small percentage of patients benefit from immunotherapy. A growing number of studies have demonstrated that the prognosis of patients with cutaneous melanoma is closely related to long non-coding RNA and the tumor immune microenvironment.

Methods

We downloaded RNA expression data and immune-related gene lists of cutaneous melanoma patients separately from The Cancer Genome Atlas database and ImmPort website and identified immune-related lncRNAs by co-expression analysis. The prognostic model was constructed by applying least absolute shrinkage and selection operator regression, and all patients were classified into high- and low-risk groups according to the risk score of the model. We evaluated the differences between the two groups in terms of survival outcomes, immune infiltration, pathway enrichment, chemotherapeutic drug sensitivity and immune checkpoint gene expression to verify the impact of lncRNA signature on clinical prognosis and immunotherapy efficacy.

Results

By correlation analysis and LASSO regression analysis, we constructed an immune-related lncRNA prognostic model based on five lncRNA: HLA-DQB1-AS1, MIR205HG, RP11-643G5.6, USP30-AS1 and RP11-415F23.4. Based on this model, we plotted Kaplan-Meier survival curves and time-dependent ROC curves and analyzed its ability as an independent prognostic factor for cutaneous melanoma in combination with clinicopathological features. The results showed that these lncRNA signature was an independent prognostic factor of cutaneous melanoma with favorable prognostic ability. Our results also show a higher degree of immune infiltration, higher expression of immune checkpoint-associated genes, and better outcome of immunotherapy in the low-risk group of the lncRNA signature.

Conclusion

The 5 immune-related lncRNA signatures constructed in our study can predict the prognosis of cutaneous melanoma and contribute to the selection of immunotherapy.

Metastatic disease to the liver: Locoregional therapy strategies and outcomes

Secondary cancers of the liver are more than twenty times more common than primary tumors and are incurable in most cases. While surgical resection and systemic chemotherapy are often the first-line therapy for metastatic liver disease, a majority of patients present with bilobar disease not amenable to curative local resection. Furthermore, by the time metastasis to the liver has developed, many tumors demonstrate a degree of resistance to systemic chemotherapy. Fortunately, catheter-directed and percutaneous locoregional approaches have evolved as major treatment modalities for unresectable metastatic disease. These novel techniques can be used for diverse applications ranging from curative intent for small localized tumors, downstaging of large tumors for resection, or locoregional control and palliation of advanced disease. Their use has been associated with increased tumor response, increased disease-free and overall survival, and decreased morbidity and mortality in a broad range of metastatic disease. This review explores recent advances in liver-directed therapies for metastatic liver disease from primary colorectal, neuroendocrine, breast, and lung cancer, as well as uveal melanoma, cholangiocarcinoma, and sarcoma. Therapies discussed include bland transarterial embolization, chemoembolization, radioembolization, and ablative therapies, with a focus on current treatment approaches, outcomes of locoregional therapy, and future directions in each type of metastatic disease.

HLA-G expression in melanomas

OBJECTIVE

Human leukocyte antigen G (HLA-G) is a non-classical HLA class I molecule involved in inducing tolerance at the feto-maternal interface and in escape of immune response by tumor cells. The aim of the study is to review the published literature on the expression of HLA-G in malignant melanomas and its clinicopathological and prognostic correlates.

METHODS

A systematic search was carried out in electronic databases. Studies dealing with HLA-G expression in surgically-removed human samples were retrieved and analyzed.

RESULTS

Of 1737 retrieved articles, 16 were included. The main themes regarded HLA-G expression in malignant melanocytic lesions, assessed by immunohistochemistry (IHC), soluble or molecular techniques, and its relationship with clinicopathological features, such as tumor thickness and malignant behavior. Overall significant HLA-G expression was found in 460/843 tumors (55%), and specifically in 251/556 melanomas (45%) evaluated with IHC, in 208/250 cases (83%) examined with soluble methods and in 13/23 melanoma lesions (57%) tested with polymerase chain reaction. Despite the correlation with parameters indicating an aggressive behavior, no studies demonstrated any prognostic value of HLA-G expression. Furthermore, uveal melanomas were constantly negative for this biomarker.

CONCLUSION

Overall, published data indicate that while HLA-G is involved in the interactions between melanomas and the immune system, it is unlikely to be the only factor to play such a role, therefore making it difficult to designate it as a prognostically relevant molecule. Evidence further suggests that HLA-G is not implicated in the immunobiology of uveal melanomas.

Clear cell sarcoma-like/malignant gastrointestinal neuroectodermal tumor of the tongue: a clinicopathologic and molecular case report

Malignant gastrointestinal neuroectodermal tumor (M-GNET) and clear cell sarcoma (CCS) of soft tissue represent closely related, extremely rare, malignant mesenchymal neoplasm of uncertain differentiation. Both entities are characterized genetically by the same molecular alterations represented by the presence of EWSR1-ATF1 and, more rarely, EWSR1-CREB1 fusion genes. The latter translocation seems to be more represented in M-GNET that, despite significant morphologic overlap with CCS, tends to lack overt features of melanocytic differentiation. Most M-GNET occur in the lower gastrointestinal tract, whereas occurrence in the upper tract has been reported only exceptionally. The differential diagnosis represents a major challenge, and accurate diagnosis impact significantly on therapeutic planning. We herein report the clinicopathologic features of a molecularly confirmed M-GNET that arose at the base of the tongue and review the pertinent literature.

Moving Immune Therapy Forward Targeting TME

The host immune system shapes the fate of tumor progression. Hence, manipulating patients' immune system to activate host immune responses against cancer pathogenesis is a promising strategy to develop effective therapeutic interventions for metastatic and drug-resistant cancers. Understanding the dynamic mechanisms within the tumor microenvironment (TME) that contribute to heterogeneity and metabolic plasticity is essential to enhance the patients' responsiveness to immune targeted therapies. Riera-Domingo et al. (Riera-Domingo C, Audige A, Granja S, Cheng WC, Ho PC, Baltazar F, Stockmann C, Mazzone, M. Physiol Rev 100: 1-102, 2020) describe the immune landscape within the TME and highlight the significance of metabolic and hypoxic signatures that impact immune function and response to immunotherapy strategies. Current literature in this field confirms that targeting tumor metabolism and the acidic microenvironment commonly associated with tumors may present viable strategies to modulate the host immune system in favor of response to immune targeted therapies. However, development of better tools to understand tumor-immune interactions and identify mechanisms driving nonresponders, more innovative clinical trial design, and new therapies will need to be identified to move the field forward. Personalized immune therapies incorporating metabolic and microbiome-based gene signatures to influence the therapeutic response and novel methods to generate immunologically "hot" tumors are at the forefront of immunotherapy currently. The combination of these approaches with clinically approved immunotherapies will be valuable moving forward.