Unveiling the tumor immune microenvironment of organ-specific melanoma metastatic sites

[18F]-FDG PET-CT in Malignant Melanoma

Background/Objectives: Malignant melanoma (MM) is an aggressive neoplasm with a rising global incidence. Accurate staging and risk stratification are essential for guiding therapeutic decisions and improving patient prognosis. [18F]-FDG PET-CT enables the non-invasive assessment of tumor metabolic activity, offering a valuable adjunct to histopathological evaluation. However, the correlation between PET-CT findings and established prognostic markers in MM, such as Breslow thickness, ulceration, and mitotic rate, remains insufficiently explored. Methods: This retrospective observational study included 61 patients diagnosed with MM, of whom 48 met the inclusion criteria. Quantitative and qualitative variables such as SULmax, Breslow thickness, Ki-67 expression, and mitotic rate were analyzed using descriptive statistics, while correlations between PET-CT findings, SLNB, and histopathological characteristics were assessed using Spearman's correlation test. A p-value < 0.05 was considered statistically significant. Results: Significant associations were identified between ulceration and both overall metastases (p = 0.01) and pulmonary metastases (p = 0.02). Breslow thickness showed a positive correlation with metastatic spread (p = 0.01), reinforcing its role as a key prognostic indicator. Perineural and vascular invasion were significantly associated with intra-abdominal metastases (p < 0.001 and p = 0.0007, respectively). Tumor-infiltrating lymphocytes (TILs) were inversely correlated with intra-abdominal metastases (p = 0.05), while sentinel lymph node positivity correlated with the presence of regional (p = 0.008) and distant (p = 0.02) metastases. Additionally, subcutaneous SULmax values were significantly higher in male patients compared to females (p = 0.04). Conclusions: Integrating PET-CT metabolic parameters with histopathological markers enhances the assessment of MM aggressiveness and metastatic potential. By refining risk stratification, PET-CT may contribute to personalized therapeutic strategies and improved patient management in MM.

Perspectives on the role of "-Omics" in predicting response to immunotherapy

The annual Immuno-Oncology "Think Tank" held in October 2023 in Siena reviewed the rapidly evolving systems-biological approaches which are now providing a deeper understanding of tumor and tumor microenvironment heterogeneity. Based on this understanding opportunities for novel therapies may be identified to overcome resistance to immunotherapy. There is increasing evidence that malignant disease processes are not limited to purely intracellular or genetic events but constitute a dynamic interaction between the host and disease. Tumor responses are influenced by many host tissue determinants across different cellular compartments, which can now be investigated by high-throughput molecular profiling technologies, often labelled with a suffix "-omics". "Omics" together with ever increasing computational power, fast developments in machine learning, and high-resolution detection tools offer an unrivalled opportunity to connect high-dimensional data and create a holistic view of disease processes in cancer. This review describes advances in several state-of-the-art "-omics" approaches with perspectives on how these can be applied to the clinical development of new immunotherapeutic strategies and ultimately adopted in clinical practice.

Systemic immune characteristics predicting toxicity to immune checkpoint inhibitors in patients with advanced breast cancer

BACKGROUND

Immune checkpoint inhibitors (ICIs) are among the most promising treatment options for cancer. However, frequent and sometimes life-threatening immune-related adverse events (irAEs) are associated with ICI treatment. Therefore, it is imperative to establish a model for predicting the risk of irAEs to identify high-risk groups, enable more accurate clinical risk‒benefit analysis for ICI treatment and decrease the incidence of irAEs. However, no ideal model for predicting irAEs has been applied in clinical practice. The aim of this study was to analyze the systemic immune characteristics of patients with irAEs and establish a model for predicting the risk of irAEs.

METHODS

We conducted a study to monitor irAEs in patients with advanced breast cancer undergoing immunotherapy during and following the treatment course. Peripheral blood mononuclear cells (PBMCs) were collected before and after two cycles of therapy. Mass cytometry time-of-flight (CyTOF) was employed to identify baseline and posttreatment immune cell subpopulations, and the relationships between the proportions of cells in these subpopulations and the occurrence of irAEs were explored. Additionally, we conducted subgroup analyses stratified by the anatomic location and time of onset of irAEs. Furthermore, we developed a logistic regression model to predict the risk of irAEs and validated this model using two independent validation cohorts from the Gene Expression Omnibus (GEO) database (accession numbers GSE189125 and GSE186143).

RESULTS

By analyzing 106 blood samples and samples from two independent validation cohorts (n = 16 and 60 patients), we found that high proportions of CXCR3+CCR6+CD4+ T cells and CD38+CD86+CXCR3+CCR6+CD8+ T cells and a low proportion of CXCR3lowCD56dim natural killer (NK) cells at baseline were significantly correlated with the incidence of irAEs (P = 0.0029, P < 0.001, and P = 0.0017, respectively). In the subgroup analysis, we observed consistent results in patients with immune-related pneumonitis (ir-pneumonitis) and immune-related thyroiditis (ir-thyroiditis). In the early irAE group, the baseline proportion of CXCR3+CCR6+CD4+ T cells was greater than that in the late irAE group (P = 0.011). An analysis of PBMCs before and after ICI treatment revealed thatthe dynamic changes in the proportions of naïve CD4+ T cells and CXCR3lowCD56dim NK cells were closely related to irAE occurrence. Finally, we ultimately developed a model for predicting the risk of irAEs, which yielded an area under the receiver operating characteristic curve (AUROC) of 0.79 in the training cohort and an AUROC of 0.75 in the single-cell validation cohort (GSE189125).

CONCLUSIONS

These findings indicate that different populations of immune cells are associated with different irAEs and that characterization of these cells may be used as biomarkers to predict the risk of specific toxicities. This will facilitate the management of irAEs and may lead to a reduction in the incidence of irAEs.

Liver Metastases are Associated with a Short Post-Progression Survival in a Real-World Group of Patients with Melanoma Treated with Checkpoint Inhibitors

INTRODUCTION

The introduction of immunotherapy (IT) has transformed clinical care of patients with metastatic melanoma. However, many patients still die as a result of progressive disease. Here we analyzed how IT improved survival in a real-world setting. Additionally, we investigated whether IT alters the dynamics and pattern of metastatic progression in different organs resulting from tissue-specific immune microenvironments.

METHODS

We retrospectively compared a group of 61 patients with metastatic melanoma (24 female, 37 male) treated with IT between 2015 and 2018 with a historical control group of 56 patients with metastatic melanoma (21 female, 35 male) treated with chemotherapy between 2005 and 2008 regarding treatment response rates and overall survival as well as the timing and distribution of metastatic progression.

RESULTS

Patients with metastatic melanoma treated with IT showed increased response rates and longer overall survival when compared with patients treated with chemotherapy. In addition, treatment with IT altered the dynamics but not the pattern of metastatic progression when compared with treatment with chemotherapy. Interestingly, patients receiving IT lived significantly longer after metastatic progression to lymph nodes, lungs and brain, but not after metastatic progression to the liver.

CONCLUSION

Our results confirm the efficacy of IT in a real-world setting. The altered dynamics of metastases supports studies suggesting a unique role of immune privilege in the liver tissue microenvironment that increases resistance to immunotherapy.

Biofluorescence imaging-guided spatial metabolic tracing: In vivo tracking of metabolic activity in circulating tumor cell-mediated multi-organ metastases

Circulating tumor cells (CTC) are considered metastatic precursors that are shed from the primary or metastatic deposits and navigate the bloodstream before undergoing extravasation to establish distant metastases. Metabolic reprogramming appears to be a hallmark of metastatic progression, yet current methods for evaluating metabolic heterogeneity within organ-specific metastases in vivo are limited. To overcome this challenge, we present Biofluorescence Imaging-Guided Spatial Metabolic Tracing (BIGSMT), a novel approach integrating in vivo biofluorescence imaging, stable isotope tracing, stain-free laser capture microdissection, and liquid chromatography-mass spectrometry. This innovative technology obviates the need for staining or intricate sample preparation, mitigating metabolite loss, and substantially enhances detection sensitivity and accuracy through chemical derivatization of polar metabolites in central carbon pathways. Application of BIGSMT to a preclinical CTC-mediated metastasis mouse model revealed significant heterogeneity in the in vivo carbon flux from glucose into glycolysis and the tricarboxylic acid (TCA) cycle across distinct metastatic sites. Our analysis indicates that carbon predominantly enters the TCA cycle through the enzymatic reaction catalyzed by pyruvate dehydrogenase. Thus, our spatially resolved BIGSMT technology provides fresh insights into the metabolic heterogeneity and evolution during melanoma CTC-mediated metastatic progression and points to novel therapeutic opportunities.

Epithelial-Mesenchymal Transition in Non-Small Cell Lung Cancer Management: Opportunities and Challenges

Lung cancer, the leading cause of death worldwide, is associated with the highest morbidity. Non-small cell lung cancer (NSCLC) accounts for 80-85% of lung cancer cases. Advances in the domain of cancer treatment have improved the prognosis and quality of life of patients with metastatic NSCLC. Nevertheless, tumor progression or metastasis owing to treatment failure caused by primary or secondary drug resistance remains the cause of death in the majority of cases. Epithelial-mesenchymal transition (EMT), a vital biological process wherein epithelial cancer cells lose their inherent adhesion and transform into more invasive mesenchymal-like cells, acts as a powerful engine driving tumor metastasis. EMT can also induce immunosuppression in the tumor environment, thereby promoting cancer development and poor prognosis among patients with NSCLC. This review aims to elucidate the effect of EMT on metastasis and the tumor immune microenvironment. Furthermore, it explores the possible roles of EMT inhibition in improving the treatment efficacy of NSCLC. Targeting EMT may be an ideal mechanism to inhibit tumor growth and progression at multiple steps.

Organ-Specific Immune Setpoints Underlie Divergent Immune Profiles across Metastatic Sites in Breast Cancer

Immune composition within the tumor microenvironment (TME) plays a central role in the propensity of cancer cells to metastasize and respond to therapy. Previous studies have suggested that the metastatic TME is immune-suppressed. However, limited accessibility to multiple metastatic sites within patients has made assessing the immune TME difficult in the context of multiorgan metastases. We utilized a rapid postmortem tissue collection protocol to assess the immune composition of numerous sites of breast cancer metastasis and paired tumor-free tissues. Metastases had comparable immune cell densities and compositions to paired tumor-free tissues of the same organ type. In contrast, immune cell densities in both metastatic and tumor-free tissues differed significantly between organ types, with lung immune infiltration being consistently greater than that in the liver. These immune profiling results were consistent between flow cytometry and multiplex immunofluorescence-based spatial analysis. Furthermore, we found that granulocytes were the predominant tumor-infiltrating immune cells in lung and liver metastases, and these granulocytes comprised most PD-L1-expressing cells in many tissue sites. We also identified distinct potential mechanisms of immunosuppression in lung and liver metastases, with the lung having increased expression of PD-L1+ antigen-presenting cells and the liver having higher numbers of activated regulatory T cells and HLA-DRlow monocytes. Together, these results demonstrate that the immune contexture of metastases is dictated by organ type and that immunotherapy strategies may benefit from unique tailoring to the tissue-specific features of the immune TME.

Differential T cell accumulation within intracranial and subcutaneous melanomas is associated with differences in intratumoral myeloid cells

Patients with metastatic brain melanomas (MBM) experience shorter-lasting survival than patients with extracranial metastases, and this is associated with a higher fraction of dysfunctional CD8 T cells. The goal of this study was to understand the underlying cause of T cell dysfunction in MBM. To accomplish this, we compared murine B16 melanomas implanted intracranially (IC) or subcutaneously (SC). CD8 T cell activation was not altered, but representation in IC tumors was lower. Transferred activated or naïve CD8 T cells accumulated in similar numbers in both tumors, suggesting that the vasculature does not differentially impair T cell presence. Surprisingly, we found no evidence for T cell activation in draining lymph nodes of SC or IC tumor-bearing mice, consistent with the fact that dendritic cells (DC) that had acquired tumor antigen showed an immature phenotype. Instead, T cell activation occurred within both tumors, where the majority of tumor antigen+ myeloid cells were found. While, the numbers of intratumoral DC were comparable, those in IC tumors acquired less tumor antigen, and were alternatively matured based on upregulation of MHCII without upregulation of CD86. Additionally, in IC tumors, the largest population of tumor antigen+ myeloid cells were microglia. However, their presence did not influence either antigen acquisition or the phenotype of other myeloid cell populations. Overall, our data suggest that diminished representation of CD8 T cells in IC tumors is a consequence of alternatively matured DC and/or microglia that induce distinctly activated T cells, which ultimately fail to continue to accumulate inside the tumor.

Melanoma and sex hormones: Pathogenesis, progressive disease and response to treatments

Cutaneous melanoma represents the fifth tumor in terms of incidence in young adults, with a major involvement of males than females. Despite the significant changes in available effective treatments for cutaneous melanoma, there is still a proportion of patients that do not benefit long-term disease control with immune checkpoint inhibitors and/or BRAF/MEK inhibitors, and eventually develop progressive disease. In addition to the emerging biomarkers under investigation to understand resistance to treatments, recent studies resumed the role of sex hormones (estrogens, progesterone and androgens) in melanoma patients. In the last decades, the impact of sex hormones has been considered controversial in melanoma patients, but actual growing preclinical and clinical evidence underline the potential influence on melanoma cells' growth, tumor microenvironment, the immune system and consequently on the course of disease.This review will provide available insights on the role of sex hormones in melanoma pathogenesis, disease progression and response/resistance to systemic treatments. We will also offer an overview on the recent studies on the theme, describing the hormonal contribution to disease response and the interaction with targeted therapies and immune-checkpoint inhibitors in cutaneous melanoma patients, illustrating an insight into future research in this field.

Survival outcomes in patients with de novo metastatic Merkel cell carcinoma according to site of metastases

Introduction

Merkel cell carcinoma (MCC) is a rare and aggressive neuroendocrine malignancy of the skin with a predilection for metastases. This study investigates the clinical outcomes in patients presenting with de novo Stage IV MCC according to the metastatic site(s) at presentation.

Materials and methods

Patients who presented with one or more sites of distant metastatic MCC at initial diagnosis between 2009 and 2023 were identified. The presence or absence of one or more metastases in each organ was categorized for each patient at the time of diagnosis. Overall survival (OS) and progression-free survival (PFS) were estimated using the Kaplan-Meier method. Competing risk analysis was used to estimate the cumulative occurrence risk of MCC-specific death. Fisher's exact test was used for response rate analysis. Results were considered statically significant if p < 0.05.

Results

Thirty-four patients presented with de novo distant metastatic MCC. There was no association between the number of metastatic sites at diagnosis and OS (p= 0.58), PFS (p=0.79), or response rates (p=0.53). However, the presence of bone metastases was associated with significantly shorter OS (8.2 versus 25.2 months, HR: 2.4, 95% CI 1.01-5.7, p= 0.04). MCC-specific death in patients with lymph node metastases was significantly lower than in patients without (HR: 0.28, 95% CI: 0.09-0.87, p= 0.013). The presence of bone metastases tended to associate with an increased risk of MCC-specific death, although not statistically significant. The location of metastases was not associated with the response rate to first-line treatment. There was no significant association between site of metastases and PFS.

Conclusion

In this cohort of patients with de novo metastatic MCC, the presence of bone metastases, but not the number of organs involved, was associated with significantly worse OS. The presence of lymph node metastases was associated with lower MCC-specific death. Further research is warranted in larger cohorts to investigate the impact of the location of metastases on clinical outcomes.

Mapping the single cell spatial immune landscapes of the melanoma microenvironment

Melanoma is a highly immunogenic malignancy with an elevated mutational burden, diffuse lymphocytic infiltration, and one of the highest response rates to immune checkpoint inhibitors (ICIs). However, over half of all late-stage patients treated with ICIs will either not respond or develop progressive disease. Spatial imaging technologies are being increasingly used to study the melanoma tumor microenvironment (TME). The goal of such studies is to understand the complex interplay between the stroma, melanoma cells, and immune cell-types as well as their association with treatment response. Investigators seeking a better understanding of the role of cell location within the TME and the importance of spatial expression of biomarkers are increasingly turning to highly multiplexed imaging approaches to more accurately measure immune infiltration as well as to quantify receptor-ligand interactions (such as PD-1 and PD-L1) and cell-cell contacts. CyTOF-IMC (Cytometry by Time of Flight - Imaging Mass Cytometry) has enabled high-dimensional profiling of melanomas, allowing researchers to identify complex cellular subpopulations and immune cell interactions with unprecedented resolution. Other spatial imaging technologies, such as multiplexed immunofluorescence and spatial transcriptomics, have revealed distinct patterns of immune cell infiltration, highlighting the importance of spatial relationships, and their impact in modulating immunotherapy responses. Overall, spatial imaging technologies are just beginning to transform our understanding of melanoma biology, providing new avenues for biomarker discovery and therapeutic development. These technologies hold great promise for advancing personalized medicine to improve patient outcomes in melanoma and other solid malignancies.

Anti-PD-1 alone or in combination with anti-CTLA-4 for advanced melanoma patients with liver metastases

BACKGROUND

The combination of anti-PD-1 and anti-CTLA-4 has been associated with improvement in response and survival over anti-PD-1 monotherapy in unselected patients with advanced melanoma. Whether patients with liver metastases also benefit from the combination of anti-PD-1 and anti-CTLA-4 over anti-PD-1, is unclear. In this study, we sought to assess whether the combination of anti-PD-1 and anti-CTLA-4 leads to better response, progression-free survival and overall survival, compared with anti-PD-1 monotherapy for patients with liver metastases.

METHODS

We have conducted an international multicentre retrospective study. Patients with advanced melanoma with liver metastases treated with 1st line anti-PD1 monotherapy or with anti-CTLA-4 were included. The endpoints of this study were: objective response rate, progression-free survival and overall survival.

RESULTS

With a median follow-up from commencement of anti-PD-1 monotherapy or in combination with anti-CTLA-4 of 47 months (95% CI, 42-51), objective response rate was higher with combination therapy (47%) versus anti-PD-1 monotherapy (35%) (p = 0.0027), while progression-free survival and overall survival were not statistically different between both treatment groups. However, on multivariable analysis with multiple imputation for missing values and adjusting for predefined variables, combination of anti-PD1 and anti-CTLA-4 was associated with higher objective response (OR 2.21, 1.46 - 3.36; p < 0.001), progression-free survival (HR 0.73, 0.57 - 0.92; p = 0.009) and overall survival (HR 0.71, 0.54 - 0.94; p = 0.018) compared to anti-PD1 monotherapy.

CONCLUSIONS

Findings from this study will help guide treatment selection for patients who present with liver metastases, suggesting that combination therapy should be considered for this group of patients.

Predictive Factors in Metastatic Melanoma Treated with Immune Checkpoint Inhibitors: From Clinical Practice to Future Perspective

The introduction of immunotherapy revolutionized the treatment landscape in metastatic melanoma. Despite the impressive results associated with immune checkpoint inhibitors (ICIs), only a portion of patients obtain a response to this treatment. In this scenario, the research of predictive factors is fundamental to identify patients who may have a response and to exclude patients with a low possibility to respond. These factors can be host-associated, immune system activation-related, and tumor-related. Patient-related factors can vary from data obtained by medical history (performance status, age, sex, body mass index, concomitant medications, and comorbidities) to analysis of the gut microbiome from fecal samples. Tumor-related factors can reflect tumor burden (metastatic sites, lactate dehydrogenase, C-reactive protein, and circulating tumor DNA) or can derive from the analysis of tumor samples (driver mutations, tumor-infiltrating lymphocytes, and myeloid cells). Biomarkers evaluating the immune system activation, such as IFN-gamma gene expression profile and analysis of circulating immune cell subsets, have emerged in recent years as significantly correlated with response to ICIs. In this manuscript, we critically reviewed the most updated literature data on the landscape of predictive factors in metastatic melanoma treated with ICIs. We focus on the principal limits and potentiality of different methods, shedding light on the more promising biomarkers.

VEGF Inhibitors Improve Survival Outcomes in Patients with Liver Metastases across Cancer Types-A Meta-Analysis

BACKGROUND

Liver metastases are associated with poor prognosis across cancers. Novel treatment strategies to treat patients with liver metastases are needed. This meta-analysis aimed to assess the efficacy of vascular endothelial growth factor inhibitors in patients with liver metastases across cancers.

METHODS

A systematic search of PubMed, Cochrane CENTRAL, and Embase was performed between January 2000 and April 2023. Randomized controlled trials of patients with liver metastases comparing standard of care (systemic therapy or best supportive care) with or without vascular endothelial growth factor inhibitors were included in the study. Outcomes reported included progression-free survival and overall survival.

RESULTS

A total of 4445 patients with liver metastases from 25 randomized controlled trials were included in this analysis. The addition of vascular endothelial growth factor inhibitors to standard systemic therapy or best supportive care was associated with superior progression-free survival (HR = 0.49; 95% CI, 0.40-0.61) and overall survival (HR = 0.83; 95% CI, 0.74-0.93) in patients with liver metastases. In a subgroup analysis of patients with versus patients without liver metastases, the benefit with vascular endothelial growth factor inhibitors was more pronounced in the group with liver metastases (HR = 0.44) versus without (HR = 0.57) for progression-free survival, but not for overall survival.

CONCLUSION

The addition of vascular endothelial growth factor inhibitors to standard management improved survival outcomes in patients with liver metastasis across cancers.

Gene Expressions and High Lymphocyte Count May Predict Durable Clinical Benefits in Patients with Advanced Non-Small-Cell Lung Cancer Treated with Immune Checkpoint Inhibitors

BACKGROUND

Not all patients with advanced non-small cell lung cancer (NSCLC) benefit from immune checkpoint inhibitors (ICIs). Therefore, we aimed to assess the predictive potential of gene expression profiling (GEP), peripheral immune cell counts, and clinical characteristics.

METHODS

The primary endpoint of this prospective, observational study was a durable clinical benefit (DCB) defined as progression-free survival >6 months. In a subgroup with histological biopsies of sufficient quality (n = 25), GEP was performed using the nCounter® PanCancer IO 360 panel.

RESULTS

DCB was observed in 49% of 123 included patients. High absolute lymphocyte count (ALC) and absence of liver metastases were associated with DCB (OR = 1.95, p = 0.038 and OR = 0.36, p = 0.046, respectively). GEP showed clustering of differentially expressed genes according to DCB, and a strong association between PD-L1 assessed by GEP (CD274) and immunohistochemistry (IHC) was observed (p = 0.00013). The TGF-β, dendritic cell, and myeloid signature scores were higher for patients without DCB, whereas the JAK/STAT loss signature scores were higher for patients with DCB (unadjusted p-values < 0.05).

CONCLUSIONS

ALC above 1.01 × 109/L and absence of liver metastases were significantly associated with DCB in ICI-treated patients with NSCLC. GEP was only feasible in 20% of the patients. GEP-derived signatures may be associated with clinical outcomes, and PD-L1 could be assessed by GEP rather than IHC.

Case report: Immunotherapy plus chemotherapy and stereotactic ablative radiotherapy (ICSABR): a novel treatment combination for Epstein-Barr virus-associated lymphoepithelioma-like intrahepatic cholangiocarcinoma

Epstein-Barr virus-associated lymphoepithelioma-like intrahepatic cholangiocarcinoma (EBVa LEL-ICC) is a rare tumor, characterized by a rich tumor immune microenvironment (TIME). While this tumor is reportedly sensitive to immunotherapy, its response has been inconsistent. This decreased sensitivity was associated with reduced TIME abundance. We report the case of a 53-year-old woman with EBVa LEL-ICC having reduced TIME abundance. The patient presented with a liver lesion, which was detected using ultrasound. Initially, the tumor was sensitive to immunotherapy and chemotherapy (IC), but resistance developed after a short interval. Subsequently, stereotactic ablative radiotherapy (SABR) was added to the patient's treatment, which now consisted of ICSABR. Successful tumor shrinkage was achieved with the combination therapy regimen. Thus, surgery and ICSABR are effective adjuncts to the first-line IC therapy in improving the survival rate of patients with EBVa LEL-ICC. The results of this study support multidisciplinary treatment as a viable treatment strategy for EBVa LEL-ICC.

Generation of Orthotopic Patient-Derived Xenografts in Humanized Mice for Evaluation of Emerging Targeted Therapies and Immunotherapy Combinations for Melanoma

Current methodologies for developing PDX in humanized mice in preclinical trials with immune-based therapies are limited by GVHD. Here, we compared two approaches for establishing PDX tumors in humanized mice: (1) PDX are first established in immune-deficient mice; or (2) PDX are initially established in humanized mice; then established PDX are transplanted to a larger cohort of humanized mice for preclinical trials. With the first approach, there was rapid wasting of PDX-bearing humanized mice with high levels of activated T cells in the circulation and organs, indicating immune-mediated toxicity. In contrast, with the second approach, toxicity was less of an issue and long-term human melanoma tumor growth and maintenance of human chimerism was achieved. Preclinical trials from the second approach revealed that rigosertib, but not anti-PD-1, increased CD8/CD4 T cell ratios in spleen and blood and inhibited PDX tumor growth. Resistance to anti-PD-1 was associated with PDX tumors established from tumors with limited CD8+ T cell content. Our findings suggest that it is essential to carefully manage immune editing by first establishing PDX tumors in humanized mice before expanding PDX tumors into a larger cohort of humanized mice to evaluate therapy response.

A prognostic nomogram for the cancer-specific survival of white patients with invasive melanoma at BANS sites based on the Surveillance, Epidemiology, and End Results database

OBJECTIVE

The purpose of this study was to develop a comprehensive nomogram for the cancer-specific survival (CSS) of white patients with invasive melanoma at back, posterior arm, posterior neck, and posterior scalp (BANS) sites and to determine the validity of the nomogram by comparing it with the conventional American Joint Committee on Cancer (AJCC) staging system.

METHODS

This study analyzed the patients with invasive melanoma in the Surveillance, Epidemiology, and End Results (SEER) database. R software was used to randomly divide the patients into training and validation cohorts at a ratio of 7:3. Multivariable Cox regression was used to identify predictive variables. The new survival nomogram was compared with the AJCC prognosis model using the concordance index (C-index), area under the receiver operating characteristic (ROC) curve (AUC), net reclassification index (NRI), integrated discrimination index (IDI), calibration plotting, and decision-curve analysis (DCA).

RESULTS

A novel nomogram was established to determine the 3-, 5-, and 8-year CSS probabilities of patients with invasive melanoma. According to the nomogram, the Age at Diagnosis had the greatest influence on CSS in invasive melanoma, followed by Bone Metastasis, AJCC, Stage, Liver Metastasis, Histologic Subtype, Brain Metastasis, Ulceration, and Primary Site. The nomogram had a higher C-index than the AJCC staging system in both the training (0.850 versus 0.799) and validation (0.829 versus 0.783) cohorts. Calibration plotting demonstrated that the model had good calibration ability. The nomogram outperformed the AJCC staging system in terms of AUC, NRI, IDI, and DCA.

CONCLUSION

This was the first study to develop and evaluate a comprehensive nomogram for the CSS of white patients with invasive melanoma at BANS sites using the SEER database. The novel nomogram can assist clinical staff in predicting the 3-, 5-, and 8-year CSS probabilities of patients with invasive melanoma more accurately than can the AJCC staging system.

Immune suppressive microenvironment in liver metastases contributes to organ-specific response of immunotherapy in advanced non-small cell lung cancer

BACKGROUND

The liver is a frequent site of metastases and liver metastases (LM) correlate with diminished immunotherapy efficacy in non-small cell lung cancer (NSCLC). This study aimed to analyze whether tumor response to immunotherapy differs between pulmonary lesions (PL) and LM in NSCLC and to explore potential mechanisms through multiomics analysis.

METHODS

This observational longitudinal clinical cohort study included patients with NSCLC with LM receiving immunotherapy was conducted to evaluate organ-specific tumor response of PL and LM. We collected paired PL and LM tumor samples to analyze the organ-specific difference using whole-exome sequencing, RNA sequencing, and multiplex immunohistochemistry.

RESULTS

A total of 52 patients with NSCLC with LM were enrolled to evaluate the organ-specific response of immunotherapy. The objective response rate (21.1% vs 32.7%) and disease control rate of LM were lower than that of PL (67.3% vs 86.5%). One-third of patients showed mixed response, among whom 88.2% (15/17) presented with LM increasing, but PL decreasing, while the others had the opposite pattern (p=0.002). In another independent cohort, 27 pairs of matched PL and LM tumor samples from the same individuals, including six simultaneously collected pairs, were included in the translational part. Genomic landscapes profiling revealed similar somatic mutations, tumor mutational burden, and neoantigen number between PL and LM. Bulk-RNA sequencing showed immune activation-related genes including CD8A, LCK, and ICOS were downregulated in LM. The antigen processing and presentation, natural killer (NK) cell-mediated cytotoxicity and T-cell receptor signaling pathway were enriched in PL compared with LM. Multiplex immunohistochemistry detected significantly lower fractions of CD8⁺ cells (p=0.036) and CD56^dim+ cells (p=0.016) in LM compared with PL. Single-cell RNA sequencing also characterized lower effector CD8⁺ T cells activation and NK cells cytotoxicity in LM.

CONCLUSIONS

Compared with PL, LM presents an inferior organ-specific tumor response to immunotherapy. PL and LM showed limited heterogeneity in the genomic landscape, while the LM tumor microenvironment displayed lower levels of immune activation and infiltration than PL, which might contribute to developing precise immunotherapy strategies for patients with NSCLC with LM.

A modified melanoma-molGPA scoring model: assessment of survival after and efficacy of different radiotherapy modalities in patients with melanoma brain metastases

PURPOSE

Patients with malignant melanoma brain metastases (MBMs) have poor prognoses. For MBMs, the Melanoma-molGPA is the most widely used predictive score, but its predictive value remains uncertain in patients fully treated with radiotherapy. We identified MBMs prognostic factors and modified the prognostic scoring model.

METHODS

We retrospectively analyzed patients diagnosed with MBMs between December 2010 and November 2021 for prognostic factors influencing overall survival (OS) by univariate and multivariate analyses. Nomogram plots were based on Cox regression modeling. We evaluated overall survival (OS) using Kaplan-Meier survival curves and log-rank tests.

RESULTS

The median OS (mOS) was 7.9 months. On multivariate analysis, BRAF mutation status (p < 0.001), number of brain metastases (BM) (p < 0.001), presence of liver metastases (p < 0.001), brain metastases with a midline shift (p = 0.003), Karnofsky Performance Score (p = 0.02), and lymphocyte-to-monocyte ratio (p < 0.0001) were independent OS predictors. These were incorporated into a modified risk-stratification model. Overall, whole-brain radiotherapy (WBRT) did not significantly affect mOS (mOS, 6.89 vs. 8.83 months; p = 0.07). After risk stratification using our model, WBRT resulted in no significant survival benefit in the low-risk group (mOS 10.07 vs. 13.1 months; p = 0.71) but significantly worse prognosis in the high-risk group (mOS, 2.37 vs. 6.92 months; p = 0.026).

CONCLUSION

We propose a modified model that accurately distinguishes the prognosis of patients with MBMs and guides decision-making for radiotherapy. Based on this novel model, WBRT should be cautiously selected for high-risk patients.

Ubiquitination-related biomarkers in metastatic melanoma patients and their roles in tumor microenvironment

Background

Skin cutaneous melanoma (SKCM) is the deadliest type of cutaneous malignancy. Ubiquitination is a process of protein sorting and degradation that exhibits multiple functions in the progression of various tumors. This study aimed to characterize a set of genes for ubiquitination in SKCM.

Methods

The expression patterns of ubiquitin-associated genes (URGs) and the corresponding clinical information in SKCM tissues were comprehensively analyzed based on The Cancer Genome Atlas (TCGA) database. We performed univariate and multivariate Cox proportional regression models to characterize the risk scores and identify four critical genes related to prognostic ubiquitination (HCLS1, CORO1A, NCF1 and CCRL2), which were used to construct the prognostic signatures. We also studied the effects of HCLS1, CORO1A and CCRL2 on tumor metastasis-related indicators at the cellular level through in vitro experiments.

Results

SKCM patients in the low-risk group showing a longer survival than those in the high-risk group. Characteristic risk scores correlated with several clinicopathological variables and reflected the infiltration of multiple immune cells. In addition, the knockdown of CLS1, CORO1A and CCRL2 affected cellular malignant biological behavior through the EMT signaling pathway.

Conclusion

This study provides a novel and prospective strategy to improve the clinical survival of SKCM patients.

Beyond CTLA-4 and PD-1 Inhibition: Novel Immune Checkpoint Molecules for Melanoma Treatment

More than ten years after the approval of ipilimumab, immune checkpoint inhibitors (ICIs) against PD-1 and CTLA-4 have been established as the most effective treatment for locally advanced or metastatic melanoma, achieving durable responses either as monotherapies or in combinatorial regimens. However, a considerable proportion of patients do not respond or experience early relapse, due to multiple parameters that contribute to melanoma resistance. The expression of other immune checkpoints beyond the PD-1 and CTLA-4 molecules remains a major mechanism of immune evasion. The recent approval of anti-LAG-3 ICI, relatlimab, in combination with nivolumab for metastatic disease, has capitalized on the extensive research in the field and has highlighted the potential for further improvement of melanoma prognosis by synergistically blocking additional immune targets with new ICI-doublets, antibody-drug conjugates, or other novel modalities. Herein, we provide a comprehensive overview of presently published immune checkpoint molecules, including LAG-3, TIGIT, TIM-3, VISTA, IDO1/IDO2/TDO, CD27/CD70, CD39/73, HVEM/BTLA/CD160 and B7-H3. Beginning from their immunomodulatory properties as co-inhibitory or co-stimulatory receptors, we present all therapeutic modalities targeting these molecules that have been tested in melanoma treatment either in preclinical or clinical settings. Better understanding of the checkpoint-mediated crosstalk between melanoma and immune effector cells is essential for generating more effective strategies with augmented immune response.

T Cell Immunoglobulin and Mucin Domain 3 (TIM-3) in Cutaneous Melanoma: A Narrative Review

T cell immunoglobulin and mucin domain 3 (TIM-3) is an inhibitory immunocheckpoint that belongs to the TIM gene family. Monney et al. first discovered it about 20 years ago and linked it to some autoimmune diseases; subsequent studies have revealed that some tumours, including melanoma, have the capacity to produce inhibitory ligands that bind to these receptor checkpoints on tumour-specific immune cells. We conducted a literature search using PubMed, Web of Science (WoS), Scopus, Google Scholar, and Cochrane, searching for the following keywords: "T cell immunoglobulin and mucin-domain containing-3", "TIM-3" and/or "Immunocheckpoint inhibitors" in combination with "malignant melanoma" or "human malignant melanoma" or "cutaneous melanoma". The literature search initially turned up 117 documents, 23 of which were duplicates. After verifying eligibility and inclusion criteria, 17 publications were ultimately included. A growing body of scientific evidence considers TIM-3 a valid inhibitory immuno-checkpoint with a very interesting potential in the field of melanoma. However, other recent studies have discovered new roles for TIM-3 that seem almost to contradict previous findings in this regard. All this demonstrates how common and valid the concept of 'pleiotropism' is in the TME field, in that the same molecule can behave completely or partially differently depending on the cell type considered or on temporary conditions. Further studies, large case series, and a special focus on the immunophenotype of TIM-3 are absolutely necessary in order to explore this highly promising topic in the near future.

Microenvironment-driven metabolic adaptations guiding CD8+ T cell anti-tumor immunity

The metabolic stress occurring in the tumor microenvironment (TME) hampers T cell anti-tumor immunity by disturbing T cell metabolic and epigenetic programs. Recent studies are making headway toward identifying strategies to unleash T cell activities by targeting T cell metabolism. Furthermore, efforts have been made to improve the efficacy of immune checkpoint blockade and adoptive cell transfer therapies. However, distinct treatment outcomes across different cancers raise the question of whether our understanding of the features of CD8⁺ T cells within the TME are universal, regardless of their tissue of origin. Here, we review the common and distinct environmental factors affecting CD8⁺ T cells across tumors. Moreover, we discuss how distinct tissue-specific niches are interpreted by CD8⁺ T cells based on studies on tissue-resident memory T (Trm) cells and how these insights can pave the way for a better understanding of the metabolic regulation of CD8⁺ T cell differentiation and anti-tumor immunity.

The effect of organ-specific tumor microenvironments on response patterns to immunotherapy

Immunotherapy, particularly immune checkpoint inhibitors, have become widely used in various settings across many different cancer types in recent years. Whilst patients are often treated on the basis of the primary cancer type and clinical stage, recent studies have highlighted disparity in response to immune checkpoint inhibitors at different sites of metastasis, and their impact on overall response and survival. Studies exploring the tumor immune microenvironment at different organ sites have provided insights into the immune-related mechanisms behind organ-specific patterns of response to immunotherapy. In this review, we aimed to highlight the key learnings from clinical studies across various cancers including melanoma, lung cancer, renal cell carcinoma, colorectal cancer, breast cancer and others, assessing the association of site of metastasis and response to immune checkpoint inhibitors. We also summarize the key clinical and pre-clinical findings from studies exploring the immune microenvironment of specific sites of metastasis. Ultimately, further characterization of the tumor immune microenvironment at different metastatic sites, and understanding the biological drivers of these differences, may identify organ-specific mechanisms of resistance, which will lead to more personalized treatment approaches for patients with innate or acquired resistance to immunotherapy.