Obesity Is Associated with Altered Tumor Metabolism in Metastatic Melanoma

PURPOSE

Overweight/obese (OW/OB) patients with metastatic melanoma unexpectedly have improved outcomes with immune checkpoint inhibitors (ICI) and BRAF-targeted therapies. The mechanism(s) underlying this association remain unclear, thus we assessed the integrated molecular, metabolic, and immune profile of tumors, as well as gut microbiome features, for associations with patient body mass index (BMI).

EXPERIMENTAL DESIGN

Associations between BMI [normal (NL < 25) or OW/OB (BMI ≥ 25)] and tumor or microbiome characteristics were examined in specimens from 782 patients with metastatic melanoma across 7 cohorts. DNA associations were evaluated in The Cancer Genome Atlas cohort. RNA sequencing from 4 cohorts (n = 357) was batch corrected and gene set enrichment analysis (GSEA) by BMI category was performed. Metabolic profiling was conducted in a subset of patients (x = 36) by LC/MS, and in flow-sorted melanoma tumor cells (x = 37) and patient-derived melanoma cell lines (x = 17) using the Seahorse XF assay. Gut microbiome features were examined in an independent cohort (n = 371).

RESULTS

DNA mutations and copy number variations were not associated with BMI. GSEA demonstrated that tumors from OW/OB patients were metabolically quiescent, with downregulation of oxidative phosphorylation and multiple other metabolic pathways. Direct metabolite analysis and functional metabolic profiling confirmed decreased central carbon metabolism in OW/OB metastatic melanoma tumors and patient-derived cell lines. The overall structure, diversity, and taxonomy of the fecal microbiome did not differ by BMI.

CONCLUSIONS

These findings suggest that the host metabolic phenotype influences melanoma metabolism and provide insight into the improved outcomes observed in OW/OB patients with metastatic melanoma treated with ICIs and targeted therapies. See related commentary by Smalley, p. 5.

Beyond BRAF(V600): clinical mutation panel testing by next-generation sequencing in advanced melanoma

The management of melanoma has evolved due to improved understanding of its molecular drivers. To augment the current understanding of the prevalence, patterns, and associations of mutations in this disease, the results of clinical testing of 699 advanced melanoma patients using a pan-cancer next generation sequencing (NGS) panel of hotspot regions in 46 genes were reviewed. Mutations were identified in 43 of the 46 genes on the panel. The most common mutations were BRAF^V600 (36%), NRAS (21%), TP53 (16%), BRAF^Non-V600 (6%), and KIT (4%). Approximately one-third of melanomas had >1 mutation detected, and the number of mutations per tumor was associated with melanoma subtype. Concurrent TP53 mutations were the most frequent event in tumors with BRAF^V600 and NRAS mutations. Melanomas with BRAF^Non-V600 mutations frequently harbored concurrent NRAS mutations (18%), which were rare in tumors with BRAF^V600 mutations (1.6%). The prevalence of BRAF^V600 and KIT mutations were significantly associated with melanoma subtypes, and BRAF^V600 and TP53 mutations were significantly associated with cutaneous primary tumor location. Multiple potential therapeutic targets were identified in metastatic unknown primary and cutaneous melanomas that lacked BRAF^V600 and NRAS mutations. These results enrich our understanding of the patterns and clinical associations of oncogenic mutations in melanoma.

An integrated motion capture system for evaluation of neuromuscular disease patients

There currently exist a variety of methods for evaluating movement in patients suffering from neuromuscular diseases (NMD). These tests are primarily performed in the clinical setting and evaluated by highly trained individuals, rather than evaluating patient in their natural environments (i.e., home or school). Currently available automated motion capture modalities offer a highly accurate means of assessing general motion, but are also limited to a highly controlled setting. Recent advances in MEMS technology have introduced the possibility of robust motion capture in uncontrolled environments, while minimizing user interference with self-initiated motion, especially in weaker subjects. The goal of this study is to design and evaluate a MEMS-sensor-based system for motion capture in the NMD patient population. The highly interdisciplinary effort has led to significant progress toward the implementation of a new device, which is accurate, clinically relevant, and highly affordable.