Melanoma is an immunogenic cancer with a high response rate to immune checkpoint inhibitors (ICIs). It harbors a high mutation burden compared with other cancers and, as a result, has abundant tumor-infiltrating lymphocytes (TILs) within its microenvironment. However, understanding the complex interplay between the stroma, tumor cells, and distinct TIL subsets remains a substantial challenge in immune oncology. To properly study this interplay, quantifying spatial relationships of multiple cell types within the tumor microenvironment is crucial. To address this, we used cytometry time-of-flight (CyTOF) imaging mass cytometry (IMC) to simultaneously quantify the expression of 35 protein markers, characterizing the microenvironment of 5 benign nevi and 67 melanomas. We profiled more than 220,000 individual cells to identify melanoma, lymphocyte subsets, macrophage/monocyte, and stromal cell populations, allowing for in-depth spatial quantification of the melanoma microenvironment. We found that within pretreatment melanomas, the abundance of proliferating antigen-experienced cytotoxic T cells (CD8 + CD45RO + Ki67 + ) and the proximity of antigen-experienced cytotoxic T cells to melanoma cells were associated with positive response to ICIs. Our study highlights the potential of multiplexed single-cell technology to quantify spatial cell-cell interactions within the tumor microenvironment to understand immune therapy responses.

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Dual MAPK pathway inhibition (dMAPKi) with BRAF and MEK inhibitors improves survival in BRAF V600E/K mutant melanoma, but the efficacy of dMAPKi in non-V600 BRAF mutant tumors is poorly understood. We sought to characterize the responsiveness of class II (enhanced kinase activity, dimerization dependent) BRAF mutant melanoma to dMAPKi. Tumors from patients with BRAF wild-type (WT), V600E (class I), and L597S (class II) metastatic melanoma were used to generate patient-derived xenografts (PDX). We assembled a panel of melanoma cell lines with class IIa (activation segment) or IIb (p-loop) mutations and compared these with WT or V600E/K BRAF mutant cells. Cell lines and PDXs were treated with BRAFi (vemurafenib, dabrafenib, encorafenib, and LY3009120), MEKi (cobimetinib, trametinib, and binimetinib), or the combination. We identified 2 patients with BRAF L597S metastatic melanoma who were treated with dMAPKi. BRAFi impaired MAPK signaling and cell growth in class I and II BRAF mutant cells. dMAPKi was more effective than either single MAPKi at inhibiting cell growth in all class II BRAF mutant cells tested. dMAPKi caused tumor regression in two melanoma PDXs with class II BRAF mutations and prolonged survival of mice with class II BRAF mutant melanoma brain metastases. Two patients with BRAF L597S mutant melanoma clinically responded to dMAPKi. Class II BRAF mutant melanoma is growth inhibited by dMAPKi. Responses to dMAPKi have been observed in 2 patients with class II BRAF mutant melanoma. These data provide rationale for clinical investigation of dMAPKi in patients with class II BRAF mutant metastatic melanoma.

Background: Excessive opioid prescribing after surgery has been recognised as a contributor to the current crisis of opioid addiction and overdose. Clinicians may potentially tackle this crisis by using opioid-free postoperative analgesia; however, the scientific literature addressing this approach is sparse and heterogeneous, thereby limiting robust conclusions. A scoping review was conducted to systematically map the extent, range, and nature of the literature addressing postoperative opioid-free analgesia. Methods: Eight bibliographic databases were searched for studies addressing opioid-free analgesia after a major surgery. We extracted the study characteristics, including design, country, year, surgical procedure(s), and interventions. Results were organised thematically according to surgical specialty and targeted phase of recovery: in hospital (early recovery, 24 h after operation; intermediate recovery, >24 h) and post-discharge (late recovery). Reporting was according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses statement for scoping reviews. Results: We identified 424 studies addressing postoperative opioid-free analgesia. The number of studies conducted in countries where the opioid crisis is primarily focused was remarkably low (USA, n¼11 [3%]; Canada, n¼5 [1%]). Many RCTs compared opioid-free vs opioid analgesia during hospital stay (n¼117), but few targeted analgesia post-discharge (n¼8). Studies were predominantly focused on procedures in orthopaedic, general, and gynaecological/obstetric surgery. Limited attention has been directed towards non-pharmacological pain interventions. We did not identify knowledge synthesis studies (i.e. systematic reviews and meta-analyses) focused on the comparative effectiveness of opioid-free vs opioid analgesia. Conclusions: Opioids remain a mainstay analgesic for managing pain after surgery, but alternative analgesia strategies should not be overlooked. This scoping review indicates numerous opportunities for future research targeting opioid-free postoperative analgesia. Review registration: http://www.researchregistry.com; ID: reviewregistry576.