Baseline β-catenin, programmed death-ligand 1 expression and tumour-infiltrating lymphocytes predict response and poor prognosis in BRAF inhibitor-treated melanoma patients

The impact of the immunological context on outcomes of solid cancer patients treated with genotype-matched targeted therapies: a comprehensive review

BACKGROUND

Outcomes with genotype-matched targeted therapy in solid cancer patients are heterogeneous: some have exceptional responses, whereas others have primary progression. This review explores the immunobiological features which may underlie this differential response.

METHODS

We conducted a literature review of studies assessing the impact of immune context following searches on Web of Science, Medline and Embase. Relevant outcomes include response, progression-free survival and overall survival. Data were extracted from multivariate analysis, univariate analysis or directly from Kaplan-Meier curves. Meta-analyses were carried out where three or more studies analysed the same immune factor for the same cancer type. The remaining studies were analysed descriptively.

RESULTS

In the adjuvant setting, assessment of the immune context does not highlight a group failing to derive benefit for the use of dabrafenib/trametinib after resection of BRAFV600E melanoma. Differential gene expression in exceptional responders show enrichment of genes associated with immune activation. BRAFV600E colorectal cancer patients with high cytolytic scores benefit from the addition of MEK inhibition whereas those with low scores fare better without. High programmed death-ligand 1 (PD-L1) expression is predictive of inferior outcomes to epidermal growth factor receptor (EGFR), ALK and G12C tyrosine kinase inhibitors. EGFR-mutant patients with high CD8+ T cells and PD-L1 positivity have very poor outcomes. Stromal tumour-infiltrating lymphocytes predict for efficacy of stromal-poor tumours in human epidermal growth factor receptor 2 (HER2)-positive breast cancer treated with short-course adjuvant trastuzumab. High immune metagene and single immune gene expression are predictive of benefit for chemotherapy plus trastuzumab, but not chemotherapy alone. The addition of pertuzumab or lapatanib appears to be beneficial in those with immune non-enriched microenvironments. High major histocompatibility complex (MHC)-I is negatively predictive and high MHC-II is positively predictive of outcomes with trastuzumab-based therapy.

CONCLUSIONS

To our knowledge, this is the first review assessing immunological context as a biomarker for targeted therapy. The results of this review represent an important resource to aid future translational studies in advancing stratified precision medicine oncology.

Mutation analysis in individual circulating tumor cells depicts intratumor heterogeneity in melanoma

Circulating tumor DNA (ctDNA) is the cornerstone of liquid biopsy diagnostics, revealing clinically relevant genomic aberrations from blood of cancer patients. Genomic analysis of single circulating tumor cells (CTCs) could provide additional insights into intra-patient heterogeneity, but it requires whole-genome amplification (WGA) of DNA, which might introduce bias. Here, we describe a novel approach based on mass spectrometry for mutation detection from individual CTCs not requiring WGA and complex bioinformatics pipelines. After establishment of our protocol on tumor cell line-derived single cells, it was validated on CTCs of 33 metastatic melanoma patients and the mutations were compared to those obtained from tumor tissue and ctDNA. Although concordance with tumor tissue was superior for ctDNA over CTC analysis, a larger number of mutations were found within CTCs compared to ctDNA (p = 0.039), including mutations in melanoma driver genes, or those associated with resistance to therapy or metastasis. Thus, our results demonstrate proof-of-principle data that CTC analysis can provide clinically relevant genomic information that is not redundant to tumor tissue or ctDNA analysis.

Activin A-Mediated Polarization of Cancer-Associated Fibroblasts and Macrophages Confers Resistance to Checkpoint Immunotherapy in Skin Cancer

PURPOSE

Cemiplimab is approved for the treatment of locally advanced basal cell carcinomas (BCC), although with mitigated results. We sought to interrogate the cellular and molecular transcriptional reprogramming underlying BCC resistance to immunotherapy.

EXPERIMENTAL DESIGN

Here, we combined spatial and single-cell transcriptomics to deconvolute the spatial heterogeneity of the tumor microenvironment in regard with response to immunotherapy, in a cohort of both naïve and resistant BCCs.

RESULTS

We identified subsets of intermingled cancer-associated fibroblasts (CAF) and macrophages contributing the most to CD8 T-cell exclusion and immunosuppression. Within this spatially resolved peritumoral immunosuppressive niche, CAFs and adjacent macrophages were found to display Activin A-mediated transcriptional reprogramming towards extracellular matrix remodeling, suggesting active participation to CD8 T-cell exclusion. In independent datasets of human skin cancers, Activin A-conditioned CAFs and macrophages were associated with resistance to immune checkpoint inhibitors (ICI).

CONCLUSIONS

Altogether, our data identify the cellular and molecular plasticity of tumor microenvironment (TME) and the pivotal role of Activin A in polarizing the TME towards immune suppression and ICI resistance.

Immune profile analysis of peripheral blood and tumors of lung cancer patients treated with immune checkpoint inhibitors

BACKGROUND

Immune checkpoint inhibitors (ICIs) have become central to lung cancer drug therapy, and establishing biomarkers that can predict effects and adverse events (AEs) is awaited. We prospectively analyzed the association between the immune-related molecular expression in peripheral blood mononuclear cells (PBMCs) and lung cancer tissues, and the effects of ICI monotherapy.

METHODS

Twenty-one patients with advanced non-small cell lung cancer (NSCLC) who received ICI monotherapy were included. Changes in the expression of immune-related molecules in PBMCs before and after the administration of ICI were analyzed by flow cytometry. The major histocompatibility complex (MHC) class I and programmed cell death-ligand 1 (PD-L1) expression of cancer cells, and the PD-L1, CD8 and CD103 expression of tumor infiltrating immune cells in lung cancer tissue before the administration of ICI were confirmed by immunohistochemistry (IHC).

RESULTS

Twenty-one patients were investigated, including 11 adenocarcinoma and 10 squamous cell carcinoma cases. Anti-programmed cell death protein-1 (PD-1) antibody (n=18) and anti-PD-L1 antibody (n=3) were administered. The clinical responses were graded as follows: complete response (CR) (n=1), partial response (PR) (n=7), stable disease (SD) (n=10) and progressive disease (PD) (n=3). Among immune-related molecules expressed in PBMCs, the CD103+ CD39+ CD8+ T cell change after administration closely correlated with the clinical response. In the univariate analyses of the factors associated with progression-free survival (PFS), CD103+ CD39+ CD8+ cell change after administration was identified as a significant prognostic factor, while the CD103+ CD39+ CD8+ cell change after administration and Brinkman index were independent prognostic factors in a multivariate analysis of the factors associated with PFS.

CONCLUSIONS

The CD103+ CD39+ CD8+ cell change after administration may predict the efficacy of ICIs.

Strategies to overcome DC dysregulation in the tumor microenvironment

Dendritic cells (DCs) play a key role to modulate anti-cancer immunity in the tumor microenvironment (TME). They link innate to adaptive immunity by processing and presenting tumor antigens to T cells thereby initiating an anti-tumor response. However, subsets of DCs also induce immune-tolerance, leading to tumor immune escape. In this regard, the TME plays a major role in adversely affecting DC function. Better understanding of DC impairment mechanisms in the TME will lead to more efficient DC-targeting immunotherapy. Here, we review the different subtypes and functions of DCs in the TME, including conventional DCs, plasmacytoid DC and the newly proposed subset, mregDC. We further focus on how cancer cells modulate DCs to escape from the host's immune-surveillance. Immune checkpoint expression, small molecule mediators, metabolites, deprivation of pro-immunogenic and release of pro-tumorigenic cytokine secretion by tumors and tumor-attracted immuno-suppressive cells inhibit DC differentiation and function. Finally, we discuss the impact of established therapies on DCs, such as immune checkpoint blockade. Creative DC-targeted therapeutic strategies will be highlighted, including cancer vaccines and cell-based therapies.

Bright-Field Multiplex Immunohistochemistry Assay for Tumor Microenvironment Evaluation in Melanoma Tissues

Simple Summary

Bright-field (BF) immunohistochemistry (IHC) remains the gold standard for histopathological evaluations. The development of new BF multiplex IHC could be very useful for the study and characterization of the tumor microenvironment (TME) in melanoma samples. We herein compared different BF IHC multiplex protocols for the study of TME in primary cutaneous melanoma tissues and offered the best optimized protocol for visualization and evaluation. These methodologies are studied to maximize the quality of staining considering the tissue characteristics under examination, maintaining a high level of standardization and reproducibility.

Abstract

The tumor microenvironment (TME) plays a crucial role in melanoma development, progression and response to treatment. As many of the most relevant TME cell phenotypes are defined by the simultaneous detection of more than two markers, the bright-field (BF) multiplex immunohistochemistry (IHC) technique has been introduced for the quantitative assessment and evaluation of the relative spatial distances between immune cells and melanoma cells. In the current study, we aimed to validate BF multiplex IHC techniques in the Ventana Discovery Ultra Immunostainer to be applied to the evaluation of the TME in variably pigmented melanoma tissues. The BF multiplex IHC staining was performed using different combinations of six immune-cell markers—CD3, CD4, CD8, CD20, CD68 and CD163—and the melanoma cell marker SOX10. Our results show that the BF double IHC Yellow/Purple protocol guarantees the maximum contrast in all the cell populations tested and the combination SOX10 (Green), CD8 (Yellow) and CD163 (Purple) of the BF triple IHC protocol ensures the best contrast and discrimination between the three stained cell populations. Furthermore, the labeled cells were clearly distinct and easily identifiable using the image analysis software. Our standardized BF IHC multiplex protocols can be used to better assess the immune contexts of melanoma patients with potential applications to drive therapeutic decisions within clinical trials.

Hallmarks of Resistance to Immune-Checkpoint Inhibitors

Immune-checkpoint inhibitors (ICI), although revolutionary in improving long-term survival outcomes, are mostly effective in patients with immune-responsive tumors. Most patients with cancer either do not respond to ICIs at all or experience disease progression after an initial period of response. Treatment resistance to ICIs remains a major challenge and defines the biggest unmet medical need in oncology worldwide. In a collaborative workshop, thought leaders from academic, biopharma, and nonprofit sectors convened to outline a resistance framework to support and guide future immune-resistance research. Here, we explore the initial part of our effort by collating seminal discoveries through the lens of known biological processes. We highlight eight biological processes and refer to them as immune resistance nodes. We examine the seminal discoveries that define each immune resistance node and pose critical questions, which, if answered, would greatly expand our notion of immune resistance. Ultimately, the expansion and application of this work calls for the integration of multiomic high-dimensional analyses from patient-level data to produce a map of resistance phenotypes that can be utilized to guide effective drug development and improved patient outcomes.

The clinical significance of adenomatous polyposis coli (APC) and catenin Beta 1 (CTNNB1) genetic aberrations in patients with melanoma

BACKGROUND

Melanoma-intrinsic activated β-catenin pathway, the product of the catenin beta 1 (CTNNB1) gene, has been associated with low/absent tumor-infiltrating lymphocytes, accelerated tumor growth, metastases development, and resistance to anti-PD-L1/anti-CTLA-4 agents in mouse melanoma models. Little is known about the association between the adenomatous polyposis coli (APC) and CTNNB1 gene mutations in stage IV melanoma with immunotherapy response and overall survival (OS).

METHODS

We examined the prognostic significance of somatic APC/CTNNB1 mutations in the Cancer Genome Atlas Project for Skin Cutaneous Melanoma (TCGA-SKCM) database. We assessed APC/CTNNB1 mutations as predictors of response to immunotherapies in a clinicopathologically annotated metastatic patient cohort from three US melanoma centers.

RESULTS

In the TCGA-SKCM patient cohort (n = 434) presence of a somatic APC/CTNNB1 mutation was associated with a worse outcome only in stage IV melanoma (n = 82, median OS of APC/CTNNB1 mutants vs. wild-type was 8.15 vs. 22.8 months; log-rank hazard ratio 4.20, p = 0.011). APC/CTNNB1 mutation did not significantly affect lymphocyte distribution and density. In the 3-melanoma institution cohort, tumor tissues underwent targeted panel sequencing using two standards of care assays. We identified 55 patients with stage IV melanoma and APC/CTNNB1 genetic aberrations (mut) and 169 patients without (wt). At a median follow-up of more than 25 months for both groups, mut compared with wt patients had slightly more frequent (44% vs. 39%) and earlier (66% vs. 45% within six months from original diagnosis of stage IV melanoma) development of brain metastases. Nevertheless, time-to-development of brain metastases was not significantly different between the two groups. Fortunately, mut patients had similar clinical benefits from PD-1 inhibitor-based treatments compared to wt patients (median OS 26.1 months vs. 29.9 months, respectively, log-rank p = 0.23). Less frequent mutations in the NF1, RAC1, and PTEN genes were seen in the mut compared with wt patients from the 3-melanoma institution cohort. Analysis of brain melanoma tumor tissues from a separate craniotomy patient cohort (n = 55) showed that melanoma-specific, activated β-catenin (i.e., nuclear localization) was infrequent (n = 3, 6%) and not prognostic in established brain metastases.

CONCLUSIONS

APC/CTNNB1 mutations are associated with a worse outcome in stage IV melanoma and early brain metastases independent of tumor-infiltrating lymphocyte density. However, PD1 inhibitor-based treatments provide comparable benefits to both mut and wt patients with stage IV melanoma.

An analysis of the immunological tumor microenvironment of primary tumors and regional lymph nodes in squamous cell lung cancer

Background

Various immune cells that play a central role in antitumor immunity accumulate in primary tumors and regional lymph nodes. Such cellular accumulation and the molecular expression were analyzed to elucidate the immunological tumor microenvironment.

Methods

Fifty squamous cell lung cancer patients with complete resection were included. Resected specimens from primary lung tumors and regional lymph nodes were immunostained for immune-related molecules, such as CD8, CD103, major histocompatibility complex (MHC) class I, and programmed cell death protein ligand-1 (PD-L1), and the relationship between the prognosis and clinicopathological factors was retrospectively analyzed.

Results

Tumor-infiltrating lymphocytes and CD8+ lymphocytes, intratumoral and intrastromal CD103+ lymphocytes, tumor diameter, pathological T and N factors, and pathological stage were significant prognostic factors for the disease-specific survival (DSS) in a univariate analysis. In a multivariate analysis, intratumoral and intrastromal CD103+ lymphocytes and pathological T and N factors were independent prognostic factors of the DSS. Significant concordance was found between the PD-L1 expression of primary tumors and metastatic lymph nodes as well as among tumor-infiltrating lymphocytes, CD8+ lymphocytes and CD103+ lymphocytes. Infiltration of CD103+ lymphocytes into the tumor was significantly correlated with an increased PD-L1 expression of cancer cells in both primary tumors and reginal lymph node metastases. Both the intratumoral infiltration of CD103+ lymphocytes and PD-L1 expression of cancer cells were significantly higher in lymph node metastases than in primary tumors.

Conclusions

CD103+ lymphocyte infiltration in the primary tumor was shown to be strongly involved in the prognosis.

Assessing the Prognostic Significance of Tumor-Infiltrating Lymphocytes in Patients With Melanoma Using Pathologic Features Identified by Natural Language Processing

Importance

Although tumor-infiltrating lymphocytes (TILs) are an important histopathologic characteristic reflecting host immune response in patients with melanoma, their prognostic value remains controversial. Because manual review of medical records is labor intensive, a survival analysis using a large patient cohort with comprehensive clinical and histopathologic characteristics is lacking.

Objective

To assess the prognostic significance of TILs among patients with cutaneous melanoma using a large cohort established through natural language processing (NLP) algorithms.

Design, Setting, and Participants

This retrospective cohort study analyzed the medical records of 14 436 patients with cutaneous melanoma at Brigham and Women's Hospital between June 1, 2004, and December 31, 2019. Patients were followed up to death or censored at their last clinical visit.

Main Outcome and Measures

The primary outcome was overall survival (OS). Survival analysis was conducted using Kaplan-Meier curves, the log-rank test, and Cox proportional hazards regression analysis.

Results

A total of 14 436 patients with cutaneous melanoma were identified in the institution's pathology information system. Using NLP, we established a study cohort of 2624 patients (1462 men [55.7%]; median age, 61 years [interquartile range, 50-72 years]) who had vertical growth phase melanoma with TIL status scored. Absent TILs were identified in 434 patients (16.5%), nonbrisk TILs in 1916 patients (73.0%), and brisk TILs in 274 patients (10.4%). The 5-year survival rate was 71.0% (95% CI, 65.5%-76.9%) among patients with an absence of TILs, 73.8% (95% CI, 71.1%-76.5%) among patients with nonbrisk TILs, and 85.2% (95% CI, 80.0%-90.7%) among patients with brisk TILs. Brisk TILs were significantly associated with improved OS (adjusted hazard ratio, 0.63; 95% CI, 0.42-0.95; P = .03; 14.2% OS advantage at 5 years), and nonbrisk TILs were not associated with improved OS (adjusted hazard ratio, 0.87; 95% CI, 0.68-1.11; P = .25), compared with the absence of TILs.

Conclusions and Relevance

This study provides evidence based on a large patient cohort from a single institution that suggests that brisk TILs represent an independent prognostic factor for OS among patients with primary cutaneous melanoma. The study also suggests that NLP is a highly efficient tool to facilitate large-scale analyses that involve free-text clinical data.

Role of CD8+ T lymphocyte cells: Interplay with stromal cells in tumor microenvironment

CD8+ T lymphocytes are pivotal cells in the host response to antitumor immunity. Tumor-driven microenvironments provide the conditions necessary for regulating infiltrating CD8+ T cells in favor of tumor survival, including weakening CD8+ T cell activation, driving tumor cells to impair immune attack, and recruiting other cells to reprogram the immune milieu. Also in tumor microenvironment, stromal cells exert immunosuppressive skills to avoid CD8+ T cell cytotoxicity. In this review, we explore the universal function and fate decision of infiltrated CD8+ T cells and highlight their antitumor response within various stromal architectures in the process of confronting neoantigen-specific tumor cells. Thus, this review provides a foundation for the development of antitumor therapy based on CD8+ T lymphocyte manipulation.

Discontinuation of BRAF/MEK-Directed Targeted Therapy after Complete Remission of Metastatic Melanoma-A Retrospective Multicenter ADOReg Study

The advent of BRAF/MEK inhibitors (BRAFi/MEKi) has significantly improved progression-free (PFS) and overall survival (OS) for patients with advanced BRAF-V600-mutant melanoma. Long-term survivors have been identified particularly among patients with a complete response (CR) to BRAF/MEK-directed targeted therapy (TT). However, it remains unclear which patients who achieved a CR maintain a durable response and whether treatment cessation might be a safe option in these patients. Therefore, this study investigated the impact of treatment cessation on the clinical course of patients with a CR upon BRAF/MEK-directed-TT. We retrospectively selected patients with BRAF-V600-mutant advanced non-resectable melanoma who had been treated with BRAFi ± MEKi therapy and achieved a CR upon treatment out of the multicentric skin cancer registry ADOReg. Data on baseline patient characteristics, duration of TT, treatment cessation, tumor progression (TP) and response to second-line treatments were collected and analyzed. Of 461 patients who received BRAF/MEK-directed TT 37 achieved a CR. TP after initial CR was observed in 22 patients (60%) mainly affecting patients who discontinued TT (n = 22/26), whereas all patients with ongoing TT (n = 11) maintained their CR. Accordingly, patients who discontinued TT had a higher risk of TP compared to patients with ongoing treatment (p < 0.001). However, our data also show that patients who received TT for more than 16 months and who discontinued TT for other reasons than TP or toxicity did not have a shorter PFS compared to patients with ongoing treatment. Response rates to second-line treatment being initiated in 21 patients, varied between 27% for immune-checkpoint inhibitors (ICI) and 60% for BRAFi/MEKi rechallenge. In summary, we identified a considerable number of patients who achieved a CR upon BRAF/MEK-directed TT in this contemporary real-world cohort of patients with BRAF-V600-mutant melanoma. Sustained PFS was not restricted to ongoing TT but was also found in patients who discontinued TT.

Clinical Significance of Tumor Microenvironment in Acral Melanoma: A Large Single-Institution Study of Caucasians

Background: The presence of tumor-infiltrating lymphocytes (TILs) in many studies is associated with a better prognosis in melanoma patients. Programmed death-ligand 1 (PD-L1) expression has a significant value in predicting several cancers, but its role in melanoma remains ambiguous. The study aims to report a comprehensive analysis of TILs characteristics and their impact on survival in primary acral melanoma (AM). Methods: Clinical and pathological features and survival outcomes were investigated in 70 patients with AM. Immunohistochemical quantitative analysis of TILs, including expression of CD4, CD8, FOXP3, PD-1, and PD-L1, on melanoma cells was performed. Results: Kaplan-Meier analysis showed significant differences in overall survival (OS) for CD4+ (p = 0.021), CD8+ (p = 0.037), FOXP3+ (p = 0.007), and TILs density (p = 0.043). In univariate analysis of immunohistochemical features, FOXP3, CD4, CD8, PD-1, and Melanoma Institute of Australia (MIA) grading TILs (grade, density, and distribution) were correlated with survival. The higher density of FOXP3-positive cells was an independent factor associated with better survival. Conclusions: High TILs content (classed as brisk Clark scale and marked/diffuse TILs MIA grade) regardless of its immunophenotype was associated with better survival outcomes in AM. PD-L1 expression on tumor cells did not influence OS and was independent of clinical and pathological characteristics. We demonstrated that TILs are significant biomarkers in sentinel lymph node status prediction.

Nanomaterials Enhance the Immunomodulatory Effect of Molecular Targeted Therapy

Molecular targeted therapy, a tumor therapy strategy that inhibits specific oncogenic targets, has been shown to modulate the immune response. In addition to directly inhibiting the proliferation and metastasis of tumor cells, molecular targeted drugs can activate the immune system through a variety of mechanisms, including by promoting tumor antigen processing and presentation, increasing intratumoral T cell infiltration, enhancing T cell activation and function, and attenuating the immunosuppressive effect of the tumor microenvironment. However, poor water solubility, insufficient accumulation at the tumor site, and nonspecific targeting of immune cells limit their application. To this end, a variety of nanomaterials have been developed to overcome these obstacles and amplify the immunomodulatory effects of molecular targeted drugs. In this review, we summarize the impact of molecular targeted drugs on the antitumor immune response according to their mechanisms, highlight the advantages of nanomaterials in enhancing the immunomodulatory effect of molecular targeted therapy, and discuss the current challenges and future prospects.

A Framework of Major Tumor-Promoting Signal Transduction Pathways Implicated in Melanoma-Fibroblast Dialogue

Simple Summary

Melanoma cells reside in a complex stromal microenvironment, which is a critical component of disease onset and progression. Mesenchymal or fibroblastic cell type are the most abundant cellular element of tumor stroma. Factors secreted by melanoma cells can activate non-malignant associated fibroblasts to become melanoma associate fibroblasts (MAFs). MAFs promote tumorigenic features by remodeling the extracellular matrix, supporting tumor cells proliferation, neo-angiogenesis and drug resistance. Additionally, environmental factors may contribute to the acquisition of pro-tumorigenic phenotype of fibroblasts. Overall, in melanoma, perturbed tissue homeostasis contributes to modulation of major oncogenic intracellular signaling pathways not only in tumor cells but also in neighboring cells. Thus, targeted molecular therapies need to be considered from the reciprocal point of view of melanoma and stromal cells.

Abstract

The development of a modified stromal microenvironment in response to neoplastic onset is a common feature of many tumors including cutaneous melanoma. At all stages, melanoma cells are embedded in a complex tissue composed by extracellular matrix components and several different cell populations. Thus, melanomagenesis is not only driven by malignant melanocytes, but also by the altered communication between melanocytes and non-malignant cell populations, including fibroblasts, endothelial and immune cells. In particular, cancer-associated fibroblasts (CAFs), also referred as melanoma-associated fibroblasts (MAFs) in the case of melanoma, are the most abundant stromal cells and play a significant contextual role in melanoma initiation, progression and metastasis. As a result of dynamic intercellular molecular dialogue between tumor and the stroma, non-neoplastic cells gain specific phenotypes and functions that are pro-tumorigenic. Targeting MAFs is thus considered a promising avenue to improve melanoma therapy. Growing evidence demonstrates that aberrant regulation of oncogenic signaling is not restricted to transformed cells but also occurs in MAFs. However, in some cases, signaling pathways present opposite regulation in melanoma and surrounding area, suggesting that therapeutic strategies need to carefully consider the tumor–stroma equilibrium. In this novel review, we analyze four major signaling pathways implicated in melanomagenesis, TGF-β, MAPK, Wnt/β-catenin and Hyppo signaling, from the complementary point of view of tumor cells and the microenvironment.

Melanoma: Prognostic Factors and Factors Predictive of Response to Therapy

BACKGROUND

A better understanding of prognostic factors and biomarkers that predict response to treatment is required in order to further improve survival rates in patients with melanoma. Prognostic Factors: The most important histopathological factors prognostic of worse outcomes in melanoma are sentinel lymph node involvement, increased tumor thickness, ulceration and higher mitotic rate. Poorer survival may also be related to several clinical factors, including male gender, older age, axial location of the melanoma, elevated serum levels of lactate dehydrogenase and S100B. Predictive Biomarkers: Several biomarkers have been investigated as being predictive of response to melanoma therapies. For anti-Programmed Death-1(PD-1)/Programmed Death-Ligand 1 (PD-L1) checkpoint inhibitors, PD-L1 tumor expression was initially proposed to have a predictive role in response to anti-PD-1/PD-L1 treatment. However, patients without PD-L1 expression also have a survival benefit with anti-PD-1/PD-L1 therapy, meaning it cannot be used alone to select patients for treatment, in order to affirm that it could be considered a correlative, but not a predictive marker. A range of other factors have shown an association with treatment outcomes and offer potential as predictive biomarkers for immunotherapy, including immune infiltration, chemokine signatures, and tumor mutational load. However, none of these have been clinically validated as a factor for patient selection. For combined targeted therapy (BRAF and MEK inhibition), lactate dehydrogenase level and tumor burden seem to have a role in patient outcomes.

CONCLUSION

With increasing knowledge, the understanding of melanoma stage-specific prognostic features should further improve. Moreover, ongoing trials should provide increasing evidence on the best use of biomarkers to help select the most appropriate patients for tailored treatment with immunotherapies and targeted therapies.

BRAF-Mutant Transcriptional Subtypes Predict Outcome of Combined BRAF, MEK, and EGFR Blockade with Dabrafenib, Trametinib, and Panitumumab in Patients with Colorectal Cancer

PURPOSE

The influence of the transcriptional and immunologic context of mutations on therapeutic outcomes with targeted therapy in cancer has not been well defined. BRAF V600E-mutant (BM) colorectal cancer comprises two main transcriptional subtypes, BM1 and BM2. We sought to determine the impact of BM subtype, as well as distinct biological features of those subtypes, on response to BRAF/MEK/EGFR inhibition in patients with colorectal cancer.

PATIENTS AND METHODS

Paired fresh tumor biopsies were acquired at baseline and on day 15 of treatment from all consenting patients with BM colorectal cancer enrolled in a phase II clinical trial of dabrafenib, trametinib, and panitumumab. For each sample, BM subtype, cell cycle, and immune gene signature expression were determined using RNA-sequencing (RNA-seq), and a Cox proportional hazards model was applied to determine association with progression-free survival (PFS).

RESULTS

Confirmed response rates, median PFS, and median overall survival (OS) were higher in BM1 subtype patients compared with BM2 subtype patients. Evaluation of immune contexture identified greater immune reactivity in BM1, whereas cell-cycle signatures were more highly expressed in BM2. A multivariate model of PFS incorporating BM subtype plus immune and cell-cycle signatures revealed that BM subtype encompasses the majority of the effect.

CONCLUSIONS

BM subtype is significantly associated with the outcome of combination dabrafenib, trametinib, and panitumumab therapy and may serve as a standalone predictive biomarker beyond mutational status. Our findings support a more nuanced approach to targeted therapeutic decisions that incorporates assessment of transcriptional context.

Modulation of the immune microenvironment by tumor-intrinsic oncogenic signaling

The development of cancer immunotherapies has been guided by advances in our understanding of the dynamics between tumor cells and immune populations. An emerging consensus is that immune control of tumors is mediated by cytotoxic CD8+ T cells, which directly recognize and kill tumor cells. The critical role of T cells in tumor control has been underscored by preclinical and clinical studies that observed that T cell presence is positively correlated with patient response to checkpoint blockade therapy. However, the vast majority of patients do not respond or develop resistance, frequently associated with exclusion of T cells from the tumor microenvironment. This review focuses on tumor cell-intrinsic alterations that blunt productive anti-tumor immune responses by directly or indirectly excluding effector CD8+ T cells from the tumor microenvironment. A comprehensive understanding of the interplay between tumors and the immune response holds the promise for increasing the response to current immunotherapies via the development of rational novel combination treatments.

Prospective Molecular Profiling of Circulating Tumor Cells from Patients with Melanoma Receiving Combinatorial Immunotherapy

BACKGROUND

Blood molecular profiling of circulating tumor cells (CTCs) can enable monitoring of patients with metastatic melanoma during checkpoint inhibitor immunotherapy (CII) and in combination with targeted therapies. We developed a microfluidics-based CTC platform to explore CTC profiling utility in CII-treated patients with melanoma using a melanoma messenger RNA (mRNA)/DNA biomarker panel.

METHODS

Blood samples (n = 213) were collected prospectively from 75 American Joint Committee on Cancer-staged III/IV melanoma patients during CII treatment and those enriched for CTCs. CTC profiling was performed using 5 known melanoma mRNA biomarkers and BRAF V600E DNA mutation. CTC biomarker status associations with clinical outcomes were assessed.

RESULTS

CTCs were detected in 88% of blood samples from patients with melanoma. CTC-derived biomarkers and clinical variables analyzed using classification and regression tree analysis revealed that a combination of lactate dehydrogenase, CTC-mRNA biomarkers, and tumor BRAF-mutation status was indicative of clinical outcomes for patients with stage IV melanoma (n = 52). The panel stratified low-risk and high-risk patients, whereby the latter had poor disease-free (P = 0.03) and overall survival (P = 0.02). Incorporation of a DNA biomarker with mRNA profiling increased overall CTC-detection capability by 57% compared to mRNA profiling only. RNA sequencing of isolated CTCs identified significant catenin beta 1 (CTNNB1) overexpression (P <0.01) compared to nondisease donor blood. CTC-CTNNB1 was associated with progressive disease/stable disease compared to complete-responder patient status (P = 0.02). Serial CTC profiling identified subclinical disease in patients who developed progressive disease during treatment/follow-up.

CONCLUSIONS

CTC-derived mRNA/DNA biomarkers have utility for monitoring CII, targeted, and combinatorial therapies in metastatic melanoma patients.

The density and spatial tissue distribution of CD8+ and CD163+ immune cells predict response and outcome in melanoma patients receiving MAPK inhibitors

Background

Clinical response to MAPK inhibitors in metastatic melanoma patients is heterogeneous for reasons still needing to be elucidated. As the patient immune activity contributes to treatment clinical benefit, the pre-existing level of immunity at tumor site may provide biomarkers of disease outcome to therapy. Here we investigated whether assessing the density and spatial tissue distribution of key immune cells in the tumor microenvironment could identify patients predisposed to respond to MAPK inhibitors.

Methods

Pretreatment tumor biopsies from a total of 213 patients (158 for the training set and 55 for the validation set) treated with BRAF or BRAF/MEK inhibitors within the Italian Melanoma Intergroup were stained with selected immune markers (CD8, CD163, β-catenin, PD-L1, PD-L2). Results, obtained by blinded immunohistochemical scoring and digital image analysis, were correlated with clinical response and outcome by multivariate logistic models on response to treatment and clinical outcome, adjusted for American Joint Committee on Cancer stage, performance status, lactate dehydrogenase and treatment received.

Results

Patients with high intratumoral, but not peritumoral, CD8⁺ T cells and concomitantly low CD163⁺ myeloid cells displayed higher probability of response (OR 9.91, 95% CI 2.23–44.0, p = 0.003) and longer overall survival (HR 0.34, 95% CI 0.16–0.72, p = 0.005) compared to those with intratumoral low CD8⁺ T cells and high CD163⁺ myeloid cells. The latter phenotype was instead associated with a shorter progression free survival (p = 0.010). In contrast, PD-L1 and PD-L2 did not correlate with clinical outcome while tumor β-catenin overexpression showed association with lower probability of response (OR 0.48, 95% CI 0.21–1.06, p = 0.068).

Conclusions

Analysis of the spatially constrained distribution of CD8⁺ and CD163⁺ cells, representative of the opposite circuits of antitumor vs protumor immunity, respectively, may assist in identifying melanoma patients with improved response and better outcome upon treatment with MAPK inhibitors. These data underline the role of endogenous immune microenvironment in predisposing metastatic melanoma patients to benefit from therapies targeting driver-oncogenic pathways.

Resistance mechanisms in melanoma to immuneoncologic therapy with checkpoint inhibitors

Checkpoint inhibitors act by blocking physiologic mechanisms coopted by tumor cells to evade immune surveillance, restoring the immune system's ability to identify and kill malignant cells. These therapies have dramatically improved outcomes in multiple tumor types with durable responses in many patients, leading to FDA approval first in advanced melanoma, then in many other malignancies. However, as experience with checkpoint inhibitors has grown, populations of patients who are primary nonresponders or develop secondary resistance have been the majority of cases, even in melanoma. Mechanisms of resistance include those inherent to the tumor microenvironment, the tumor cells themselves, and the function of the patient's native immune cells. This review will discuss resistance to checkpoint inhibitors in melanoma as well as possible methods to restore sensitivity.

Recent Findings in the Regulation of Programmed Death Ligand 1 Expression

With the recent approvals for the application of monoclonal antibodies that target the well-characterized immune checkpoints, immune therapy shows great potential against both solid and hematologic tumors. The use of these therapeutic monoclonal antibodies elicits inspiring clinical results with durable objective responses and improvements in overall survival. Agents targeting programmed cell death protein 1 (PD-1; also known as PDCD1) and its ligand (PD-L1) achieve a great success in immune checkpoints therapy. However, the majority of patients fail to respond to PD-1/PD-L1 axis inhibitors. Expression of PD-L1 on the membrane of tumor and immune cells has been shown to be associated with enhanced objective response rates to PD-1/PD-L1 inhibition. Thus, an improved understanding of how PD-L1 expression is regulated will enable us to better define its role as a predictive marker. In this review, we summarize recent findings in the regulation of PD-L1 expression.

A Review of the Role of Wnt in Cancer Immunomodulation

Alterations in the Wnt signaling pathway are associated with the advancement of cancers; however, the exact mechanisms responsible remain largely unknown. It has recently been established that heightened intratumoral Wnt signaling correlates with tumor immunomodulation and immune suppression, which likely contribute to the decreased efficacy of multiple cancer therapeutics. Here, we review available literature pertaining to connections between Wnt pathway activation in the tumor microenvironment and local immunomodulation. We focus specifically on preclinical and clinical data supporting the hypothesis that strategies targeting Wnt signaling could act as adjuncts for cancer therapy, either in combination with chemotherapy or immunotherapy, in a variety of tumor types.

Programmed death receptor Ligand 1 expression in eyelid sebaceous carcinoma: a consecutive case series of 41 patients

PURPOSE

A limited number of therapies are available for patients with metastatic eyelid sebaceous carcinoma (SC). Programmed death receptor Ligand 1 (PD-L1) expression and its clinical significance in sebaceous cell carcinoma are presently unknown. This study aimed to evaluate the expression level of PD-L1 in SC.

METHODS

This single centre, retrospective, and comparative study was conducted at the Ninth People's Hospital between August 1, 2013 and September 1, 2016. Twenty primary, 11 recurrent, and 10 lymph node metastatic eyelid SCs of 41 consecutive patients and paired control eyelid samples were enrolled in the study. Immunohistochemical staining of PD-L1 was performed on slides containing SC embedded in paraffin wax. Patient clinical characteristics and PD-L1 expression related to SC prognostic values were evaluated.

RESULTS

Of the 41 patients with eyelid SCs, 58.5% (24/41) were female, and 41.5% (17/41) were male. A total of 43.9% (18/41) were left-sided, and 56.1% (23/41) were right-sided. A total of 2.4% (1/41) of the SCs were located at the canthus, 51.2% (21/41) were located at the upper eyelid, 41.5% (17/41) were located at the lower eyelids, and 2.4% (1/41) invaded the lacrimal sac. A total of 24.4% of the SCs were metastatic (10/41), 48.8% (20/41) were primary tumours, and 26.8% (11/41) resulted from recurrence. A total of 48.8% (20/41) were moderately graded and 51.2% (21/41) were poorly graded. Programmed death receptor Ligand 1 (PD-L1) positive expression was found in 20 (48.8%) cases. Programmed death receptor Ligand 1 (PD-L1) expression was observed on the tumour cell membrane. Higher expression of PD-L1 was correlated with metastatic cases when compared with primary cases (F = 6.69, p = 0.001). There was a higher expression of PD-L1 in the poorly differentiated group compared with the moderately graded group (57.1% poorly graded versus 45.0% moderately graded).

CONCLUSION AND RELEVANCE

Inhibition of PD-L1 expression may be a therapeutic option for metastatic eyelid SCs, although this hypothesis needs to be tested in future clinical trials.

Prognostic value of tumor-infiltrating lymphocytes in melanoma: a systematic review and meta-analysis

Tumor-infiltrating lymphocytes (TILs) are associated with prognosis in various tumors. However, it remains controversial whether the presence of TILs is related to an improved prognosis in melanoma. This meta-analysis confirmed the favorable prognostic role of the CD3+, CD4+, CD8+, FOXP3+, and CD20+ TILs in the overall survival of melanoma patients and found an association between the TILs present and improved overall survival. Additionally, subgroup analysis demonstrated that brisk TILs were obviously associated with OS, RFS and DSS/MSS. Thus, TILs may be a predictive biomarker in melanoma. This analysis will provide more insight into the study of TILs and predictive biomarker.

Prognostic significance of CD103+ immune cells in solid tumor: a systemic review and meta-analysis

CD103 is a transmembrane heterodimer complex that mediates cell adhesion, migration, and lymphocyte homing of cell through interaction with E-cadherin. Recently, CD103+ immune cells in human carcinoma has been investigated as a prognostic factor, however, the correlation between CD103+ immune cells and survival are still elusive. Therefore, a meta-analysis was performed to determine the prognostic value of CD103+ immune cells in solid tumor. Studies relevant to the subject was searched from PubMed, Embase, and Web of Science. Ten studies including 2,824 patients were eligible for the analysis. Tumors positive for CD103+ immune cells were associated with favorable overall survival, disease-free survival, and disease-specific survival. Subgroup analysis revealed that assessing CD103+ immune cells in epithelial and total (both epithelial and stromal) areas or using whole slide section were associated with good prognosis. Furthermore, stromal CD103+ immune cells or CD103+ immune cells evaluated by tissue microarrays were not always significantly prognostic. In conclusion, these results show that CD103+ immune cells are associated with prognosis in solid tumor. However, the region of assessment and selection of material for the evaluation could affect the value of CD103 as a prognostic biomarker.

WNT Signaling in Cancer Immunosurveillance

Deregulated WNT signaling has been shown to favor malignant transformation, tumor progression, and resistance to conventional cancer therapy in a variety of preclinical and clinical settings. Accumulating evidence suggests that aberrant WNT signaling may also subvert cancer immunosurveillance, hence promoting immunoevasion and resistance to multiple immunotherapeutics, including immune checkpoint blockers. Here, we discuss the molecular and cellular mechanisms through which WNT signaling influences cancer immunosurveillance and present potential therapeutic avenues to harness currently available WNT modulators for cancer immunotherapy.

Rational combination of cancer immunotherapy in melanoma

The recent advances in cancer immunotherapy with unprecedented success in therapy of advanced melanoma represent a turning point in the landscape of melanoma treatment. Given the complexity of activation of immunological system and the physiologic multifactorial homeostatic mechanisms controlling immune responses, combinatorial strategies are eagerly needed in melanoma therapy. Nevertheless, rational selection of immunotherapy combinations should be more biomarker-guided, including not only the cancer immunogram, PD-L1 expression, interferon gene expression signature, mutational burden, and tumor infiltration by CD8+ T cells but also intratumoral T cell exhaustion and microbiota composition. In this review, we summarize the rationale to develop combination treatment strategies in melanoma and discuss biological background that could help to design new combinations in order to improve patients' outcome.

Molecular Pathways in Melanomagenesis: What We Learned from Next-Generation Sequencing Approaches

PURPOSE OF REVIEW

Conventional clinico-pathological features in melanoma patients should be integrated with new molecular diagnostic, predictive, and prognostic factors coming from the expanding genomic profiles. Cutaneous melanoma (CM), even differing in biological behavior according to sun-exposure levels on the skin areas where it arises, is molecularly heterogeneous. The next-generation sequencing (NGS) approaches are providing data on mutation landscapes in driver genes that may account for distinct pathogenetic mechanisms and pathways. The purpose was to group and classify all somatic driver mutations observed in the main NGS-based studies.

RECENT FINDINGS

Whole exome and whole genome sequencing approaches have provided data on spectrum and distribution of genetic and genomic alterations as well as allowed to discover new cancer genes underlying CM pathogenesis. After evaluating the mutational status in a cohort of 686 CM cases from the most representative NGS studies, three molecular CM subtypes were proposed: BRAFmut, RASmut, and non-BRAFmut/non-RASmut.

Predictive role of plasmatic biomarkers in advanced non-small cell lung cancer treated by nivolumab

Immune checkpoint inhibitors, as nivolumab, are used in advanced non-small cell lung cancer (NSCLC). However, no associated biomarker is validated in clinical practice with this drug. We investigated herein immune-related blood markers in patients with advanced NSCLC treated with nivolumab. Plasma of 43 consecutive patients were prospectively collected at time of the diagnosis of cancer, at the initiation of nivolumab and at the first tumour evaluation (2 months). Concentrations of PD-L1 (sPD-L1), soluble PD-L2 (sPD-L2), Interleukine-2 (sIl-2), Interferon-gamma (sIFN-γ), and Granzyme B (sGranB) were quantified by ELISA. Cell free RNA was quantified by Reverse Transcriptase -PCR), and plasmatic microRNAs (miRNAs) were evaluated by targeted sequencing. Expression of PD-L1 on tumour biopsies was performed by immunohistochemistry using E13LN. High sPD-L1 at 2 months and increase of sPD-L1 concentrations were associated with poor response and absence of clinical benefit (nivolumab treatment less than 6 months). The variation of sPD-L1 concentrations were confirmed by RNA quantification. sPD-L1 concentrations were not correlated with PD-L1 expression on corresponding tumour samples. Low sGranB at nivolumab initiation was also associated with poor response. High sPD-L1 and low sGranB were associated with poor progression-free survival (PFS) and overall survival (OS). Low sPD-L2, low sIl-2 and high sIFN-γ were associated with grade 3-4 toxicities. Finally, miRNA screening showed that patients with clinical benefit (n = 9) had down-expression of miRNA-320b and -375 compared to patients with early progression at 2 months (n = 9). In conclusion, our results highlight the interest of circulating biomarkers in patients treated with nivolumab.

Impact of oncogenic pathways on evasion of antitumour immune responses

Immunotherapeutic interventions are showing effectiveness across a wide range of cancer types, but only a subset of patients shows clinical response to therapy. Responsiveness to checkpoint blockade immunotherapy is favoured by the presence of a local, CD8+ T cell-based immune response within the tumour microenvironment. As molecular analyses of tumours containing or lacking a productive CD8+ T cell infiltrate are being pursued, increasing evidence is indicating that activation of oncogenic pathways in tumour cells can impair induction or execution of a local antitumour immune response. This Review summarizes our current knowledge of the influence of oncogenic effects on evasion of antitumour immunity.

PD-L1 status does not predict the outcome of BRAF inhibitor therapy in metastatic melanoma

BACKGROUND

Targeted therapies with BRAF plus MEK inhibitors (BRAFi; MEKi) represent the major treatment strategy for patients with BRAF-mutated metastatic melanoma (MM). Previous analyses suggested a correlation between programmed death-ligand 1 (PD-L1) expression in tumour tissues and the outcome of targeted therapies. This study investigated PD-L1 as a potential predictive biomarker of BRAFi-based targeted therapies in MM patients.

PATIENTS AND METHODS

We analysed two independent cohorts of BRAF V600-mutated MM patients undergoing BRAFi-based therapies for PD-L1 expression in pre-treatment tumour tissues. The oligocentre cohort 1 included 83 patients whose tumour tissues were analysed retrospectively with the anti-PD-L1 antibody clone E1L3N. The multicentre cohort 2 included 58 patients whose tumour tissues were analysed prospectively within the framework of the "Registry of the Arbeitsgemeinschaft Dermatologische Onkologie" (ADOREG) and "Tissue Registry in Melanoma" (TRIM) project using the anti-PD-L1 antibody clone 28-8.

RESULTS

PD-L1 expression in pre-treatment tumour tissue did not correlate with response or survival to BRAFi-based therapies in both MM patient cohorts. This finding was not influenced by retrospective versus prospective immunohistochemistry analyses, oligocentre versus multicentre cohorts or the different anti-PD-L1 antibody clones used. In cohort 1, PD-L1 positivity was detected in tumour tissue of 41.0% and 18.1% of patients (cut-off 1% and 5%, respectively). In cohort 2, 58.6% and 39.7% of patients showed PD-L1 positivity (cut-off 1% and 5%, respectively).

CONCLUSION

In two independent cohorts including a total of 141 MM patients, PD-L1 expression in tumour tissue did not correlate with the outcome of BRAFi-based treatment. Therefore, PD-L1 cannot be recommended for the use as a predictive biomarker of BRAFi-based therapy in BRAF V600-mutated MM.

Rationale for New Checkpoint Inhibitor Combinations in Melanoma Therapy

The use of monoclonal antibodies that block immunologic checkpoints, which mediate adaptive immune resistance, has revolutionized the treatment of metastatic melanoma patients. Specifically, targeting single immune suppressive molecules such as cytotoxic T lymphocyte-associated protein 4 (CTLA-4), or programmed cell death protein 1 (PD-1) expressed on T cells or its primary ligand, programmed cell death ligand 1 (PD-L1), resulted in pronounced clinical benefit for a subset of melanoma patients. Although single-agent immune checkpoint inhibitor therapy has demonstrated promising clinical activity in metastatic melanoma patients, there is still a significant proportion of patients who show primary resistance to these therapies. Increased clinical efficacy was reported in phase II and III randomized studies by co-targeting CTLA-4 and PD-1 in the treatment of advanced melanoma, indicating the existence of multiple non-redundant immunosuppressive pathways in the tumor microenvironment. Nevertheless, only 50% of patients responded to combined anti-CTLA-4 and anti-PD-1 treatment. Additionally, the combination regimen was associated with severe toxicity in >50-60% of patients. In this review we summarize the rationale for new checkpoint inhibitor combinations in melanoma therapy and discuss how biologic-driven stratification enables the design of optimal combination therapies tailored to target different tumor microenvironments.