{
  "abstract": "Background Melanoma brain metastases (MBM) affect approximately 60% of patients with metastatic melanoma and exhibit distinct molecular and immune features compared to extracranial metastases (ECM). 1 2 Prior studies have demonstrated a unique immune microenvironment in MBM, including increased CD8+ T-cell infiltration and pro-tumorigenic macrophages.3–6 However, the spatial architecture of the MBM ecosystem remains incompletely understood. In this study, we explore the immunoproteomic landscape and cellular composition of MBM.Methods A tissue microarray (TMA) comprising 353 cores of matched tumor and normal adjacent human tissue specimens from MBM or ECM was constructed. High-plex proteomic and transcriptomic analysis was performed using the Nanostring GeoMx and CosMx platforms with spatial resolution. In GeoMx Digital Spatial Profiler (DSP), a 68-plex protein panel was quantified simultaneously in three fluorescence-based tissue compartments [tumor (PMEL+/MART1+/SOX10+), leukocytes (CD45+), and macrophages (CD68+)]. A 6,000-plex RNA CosMx panel was applied for spatial transcriptomic profiling. A second independent cohort of MBM patients was applied for external validation.Results Of 52 patients with melanoma brain metastases, 60% were female (31/52) and the median age was 56. 67% (35/52) received immunotherapy (IT), and majority were located on the trunk (35%) or lower extremities (21%). 42% of cases yielded either a complete (CR) or partial (PR) response to IT, 21% had stable disease (SD), and 36% had progressive disease (PD). Patients with higher CD3+, CD4+, and CD8+ expression in the CD45+ compartment in MBM samples exhibited improved overall survival ( p = 0.027, p = 0.0053, p = 0.016). NCAM1 protein expression in both CD45+ and tumor compartments was differentially expressed in MBM samples compared with ECM (p = 0.0359, p = 0.003;figure 1A-C). IT responders (CR/PR) demonstrated higher NCAM1+ cell prevalence in the CD45+ and tumor compartments compared to non-responders (SD/PD). NCAM1 overexpression in MBM was validated in a secondary cohort, and patients with low NCAM1 expression exhibited prolonged brain metastasis-free survival (BMFS) (figure 2A-B). Spatial transcriptomic mapping revealed NCAM1 localization patterns in tumor-dense regions.Conclusions NCAM1 protein expression is elevated in MBM and may be associated with early development of brain metastasis and improved survival, suggesting NCAM1 may be a potential biomarker for MBM progression and therapeutic targeting. Further studies are warranted to elucidate its mechanistic role in tumor-immune interactions and adhesion pathways in the brain microenvironment.References Su D, Kluger H, Olino K. Educational review: clinical application of immune checkpoint blockade for the treatment of melanoma. Annals of Surgical Oncology,2024;31(3):1865–1879.Tawbi HA, Boutros C, Kok D, Robert C, McArthur G. New era in the management of melanoma brain metastases. American Society of Clinical Oncology Educational Book. 2018;38:741–750.Su DG, Schoenfeld DA, Ibrahim W, Cabrejo R, Djureinovic D, Baumann R, Rimm DL, Khan SA, Halaban R, Kluger HM, Olino K. Digital spatial proteomic profiling reveals immune checkpoints as biomarkers in lymphoid aggregates and tumor microenvironment of desmoplastic melanoma. Journal for immunotherapy of cancer. 2024;12(3):e008646.Fife C, Williams J, James F, Gregory S, Andreou T, Sunderland A, McKimmie C, Brownlie RJ, Salmond RJ, Heaton S, Errington-Mais F. Natural killer cells are required for the recruitment of CD8+ T cells and the efficacy of immune checkpoint blockade in melanoma brain metastases. Journal for ImmunoTherapy of Cancer. 2024;12(11):e009522.Fischer GM, Jalali A, Kircher DA, Lee WC, McQuade JL, Haydu LE, Joon AY, Reuben A, de Macedo MP, Carapeto FC, Yang C. Molecular profiling reveals unique immune and metabolic features of melanoma brain metastases. Cancer discovery, 2019;9(5):628–645.Biermann J, Melms JC, Amin AD, Wang Y, Caprio LA, Karz A, Tagore S, Barrera I, Ibarra-Arellano MA, Andreatta M, Fullerton BT. Dissecting the treatment-naive ecosystem of human melanoma brain metastasis. Cell. 2022;185(14):2591–2608.Ethics Approval Patient gave informed consent to participate in this study prior to its start. With the approval of the Yale University Institutional Review Board (IRB), FFPE tissue blocks and clinical information were procured from the Yale University Department of Pathology Archives.Consent Written informed consent was obtained from the patient for publication of this abstract and any accompanying images. A copy of the written consent is available for review by the Editor of this journal.Abstract 1266 Figure 1Higher expression of NCAM-1 (neuronal cell adhesion molecule-1) is found in melanoma brain metastases than extracranial metastasesAbstract 1266 Figure 2High NCAM1 expression is associated with melanoma brain metastases and reduced brain metastasis-free survival in a secondary cohort",
  "authors": [
    {
      "affiliations": [
        "Yale New Haven Hospital, Hamden, CT, USA"
      ],
      "name": "David Su"
    },
    {
      "affiliations": [
        "Yale University School of Medicine, New Haven, CT, USA"
      ],
      "name": "Noam Savion Gaiger"
    },
    {
      "affiliations": [
        "Yale Cancer Center, New Haven, CT, USA"
      ],
      "name": "David A Schoenfeld"
    },
    {
      "affiliations": [
        "Yale University School of Medicine, New Haven, CT, USA"
      ],
      "name": "Mingze Dong"
    },
    {
      "affiliations": [
        "Yale University, New Haven, CT, USA"
      ],
      "name": "Dijana Djureinovic"
    },
    {
      "affiliations": [
        "Yale New Haven Hospital, Department of Pathology, New Haven, CT, USA"
      ],
      "name": "Anjela Galan"
    },
    {
      "affiliations": [
        "Yale University School of Medicine, New Haven, CT, USA"
      ],
      "name": "Veronica Chiang"
    },
    {
      "affiliations": [
        "Yale University School of Medicine, New Haven, CT, USA"
      ],
      "name": "Adebowale Adeniran"
    },
    {
      "affiliations": [
        "Yale University School of Medicine, New Haven, CT, USA"
      ],
      "name": "Kelly Olino"
    },
    {
      "affiliations": [
        "Yale University School of Medicine, New Haven, CT, USA"
      ],
      "name": "Lucia Jilaveanu"
    },
    {
      "affiliations": [
        "Yale University, New Haven, CT, USA"
      ],
      "name": "Harriet M Kluger"
    }
  ],
  "title": "1266 Spatial profiling of melanoma brain metastases exhibit elevated neural cell adhesion molecule 1 (NCAM1) protein expression and associations with immune microenvironment and treatment response",
  "uid": "f4da50f5-b6e0-5359-8708-50b44689366e"
}