Prospective tumour mutation burden and neoantigen profiling predicts immunotherapy response in metastatic melanoma
Abstract Tumour mutation burden (TMB) is a promising biomarker in predicting immunotherapy response, yet its reproducibility across target panels needs to be established. This study assessed the reproducibility of TMB estimates in melanoma using TruSight Oncology 500 across two laboratories and compared these results with the FoundationOne CDx and QIAseq TMB IO panels. High concordances in TMB estimation, mutation calls, and BRAF and N/K/HRAS hotspot variants were observed between platforms. In a cohort of 198 pre-treatment biopsies from patients treated with immune checkpoint inhibitors, high TMB (≥10 mut/Mb) was associated with significantly improved response and progression-free survival (PFS), while [...]
GLUT1 expression, lymphocyte distribution and CD3+ T-cell metabolic subsets as predictive markers of response to immunotherapy in advanced melanoma
Abstract Background: Glycolysis, commonly used by malignant tumors for energy production, results in acidification of the tumor microenvironment (TME) through the secretion and accumulation of lactic acid. Acidosis is a potent inhibitor of immune cell function and may therefore affect T-cell infiltration and the efficacy of immunotherapy. This study aimed to characterize the metabolic tumor microenvironment and its association with lymphocyte distribution in patients with advanced melanoma treated with immune checkpoint blockade (ICB) therapies. Methods: Pre-treatment formalin-fixed, paraffin-embedded metastatic melanoma specimens from 45 patients treated with anti-PD-1 ± anti-CTLA-4 ICB were included in this study. Patients with progression-free survival (PFS) ≥ [...]
Tumor miRNA Signatures Associate with Outcomes of Patients with Stage II/III Melanoma
Abstract Purpose: Patients with stage II and resected stage III melanomas have variable clinical outcomes, providing evidence of underlying biological differences in tumors and/or the patients themselves, beyond stage. The approval of adjuvant immunotherapy for stage IIB/C and resected stage III/IV disease (and adjuvant targeted therapy for resected stage III disease) has created a pressing need to develop biomarkers to accurately distinguish patients at low risk versus high risk for recurrence and death from melanoma. miRNAs are promising biomarkers because of their stability in tissues and fluids and their demonstrated functional and prognostic roles in melanoma. We hypothesized that miRNA [...]
Characterization of the treatment-naive immune microenvironment in melanoma with BRAF mutation
Abstract Background: Patients with BRAF-mutant and wild-type melanoma have different response rates to immune checkpoint blockade therapy. However, the reasons for this remain unknown. To address this issue, we investigated the precise immune composition resulting from BRAF mutation in treatment-naive melanoma to determine whether this may be a driver for different response to immunotherapy. Methods: In this study, we characterized the treatment-naive immune context in patients with BRAF-mutant and BRAF wild-type (BRAF-wt) melanoma using data from single-cell RNA sequencing, bulk RNA sequencing, flow cytometry and immunohistochemistry (IHC). Results: In single-cell data, BRAF-mutant melanoma displayed a significantly reduced infiltration of CD8+ T cells and macrophages but also increased B cells, natural [...]
DNA Methylation Classes of Stage II and III Primary Melanomas and Their Clinical and Prognostic Significance
Abstract Purpose: Patients with stage II and III cutaneous primary melanoma vary considerably in their risk of melanoma-related death. We explore the ability of methylation profiling to distinguish primary melanoma methylation classes and their associations with clinicopathologic characteristics and survival. Materials and methods: InterMEL is a retrospective case-control study that assembled primary cutaneous melanomas from American Joint Committee on Cancer (AJCC) 8th edition stage II and III patients diagnosed between 1998 and 2015 in the United States and Australia. Cases are patients who died of melanoma within 5 years from original diagnosis. Controls survived longer than 5 years without evidence of [...]
Do BRAF-targeted therapies have a role in the era of immunotherapy?
Abstract Over half of cutaneous melanomas have BRAF mutations, with this mutation being more prevalent in younger patients who often present with more aggressive disease. BRAF-targeted therapy and checkpoint inhibitor immunotherapy have led to marked improvements in outcomes for patients with BRAF-mutant melanoma. Despite these advances, novel combinatorial strategies are vital given that more than half of advanced melanoma patients will still die due to melanoma. Translational evidence has suggested potential immunostimulatory effects of BRAF-targeted therapies, yet their combination with immunotherapy has shown limited clinical success. The pathways that lead to acquired resistance to targeted therapy, which may confer [...]
Neoadjuvant triplet immune checkpoint blockade in newly diagnosed glioblastoma.
Abstract Glioblastoma (GBM) is an aggressive primary adult brain tumor that rapidly recurs after standard-of-care treatments, including surgery, chemotherapy and radiotherapy. While immune checkpoint inhibitor therapies have transformed outcomes in many tumor types, particularly when used neoadjuvantly or as a first-line treatment, including in melanoma brain metastases, they have shown limited efficacy in patients with resected or recurrent GBM. The lack of efficacy has been attributed to the scarcity of tumor-infiltrating lymphocytes (TILs), an immunosuppressive tumor microenvironment and low tumor mutation burden typical of GBM tumors, plus exclusion of large molecules from the brain parenchyma. We hypothesized that upfront [...]
G9a Inhibition Enhances Checkpoint Inhibitor Blockade Response in Melanoma.
Abstract Purpose: G9a histone methyltransferase exerts oncogenic effects in several tumor types and its inhibition promotes anticancer effects. However, the impact on checkpoint inhibitor blockade response and the utility of G9a or its target genes as a biomarker is poorly studied. We aimed to examine whether G9a inhibition can augment the efficacy of checkpoint inhibitor blockade and whether LC3B, a G9a target gene, can predict treatment response. Experimental design: Clinical potential of LC3B as a biomarker of checkpoint inhibitor blockade was assessed using patient samples including tumor biopsies and circulating tumor cells from liquid biopsies. Efficacy of G9a inhibition to enhance checkpoint [...]
Multiomic profiling of checkpoint inhibitor-treated melanoma: Identifying predictors of response and resistance, and markers of biological discordance.
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Tissue-Based Profiling Techniques to Achieve Precision Medicine in Cancer: Opportunities and Challenges in Melanoma.
Abstract Immunotherapies targeting the programmed cell death 1 (PD-1) and cytotoxic T-lymphocyte antigen 4 (CTLA-4) checkpoint receptors have revolutionized the treatment of metastatic melanoma. However, half of the treated patients do not respond to or eventually progress on standard therapies and many experience adverse events as a result of drug toxicity. The identification of accurate biomarkers of clinical outcomes are required in order to move away from the one-size-fits-all treatment approach of standard clinical practice and toward a more personalized approach to enable the administration of the optimal therapy for any given patient and further improve patient outcomes. Recent [...]