{
  "abstract": "Bone marrow represents a unique microenvironment enriched with both immunosuppressive cells and immune-activating functions. However, its role in metastasis and response to immunotherapy remains poorly understood. We report a case of sarcomatoid clear cell renal cell carcinoma with systemic bone marrow metastasis that achieved a complete response to ipilimumab plus nivolumab. Using matched pretreatment and post-treatment bone marrow samples, we performed integrative immune profiling. Pretreatment analyses showed abundant CD14+ myeloid cells, phenotypically consistent with myeloid-derived suppressor cell (MDSC)-like populations, together with CD8+ T cells. RNA-seq-based deconvolution revealed a predominance of monocytic-MDSC-like cells, which were selectively reduced after treatment with a shift toward monocyte and neutrophil-associated cells. Paired single-sample gene set enrichment analysis demonstrated that immunosuppressive (MDSC-like populations and TGF-β), and immune-activating (CD8+ T cell, interferon-gamma) pathways coexisted at baseline and were broadly attenuated following treatment. These findings suggest that the bone marrow microenvironment harbored a hybrid immune state characterized by concurrent inflammatory and immunosuppressive programs. The subsequent global contraction of both programs suggests that immune remodeling primarily reflects the resolution of tumor-driven immune activation following tumor eradication, rather than the effect from immune checkpoint inhibitors. This case highlights that even in an immune-restrictive niche, latent but functional antitumor immunity can be unleashed by immune checkpoint blockade.",
  "authors": [
    {
      "affiliations": [
        "Department of Medical Oncology, Cancer Institute Hospital of Japanese Foundation For Cancer Research, Koto, Tokyo, Japan"
      ],
      "name": "Yuji Miura"
    },
    {
      "affiliations": [
        "Department of Urology, Yokohama City University, Yokohama, Japan"
      ],
      "name": "Ryosuke Jikuya"
    },
    {
      "affiliations": [
        "Department of Medical Oncology, Toranomon Hospital, Minato, Japan"
      ],
      "name": "Asaki Saijo"
    },
    {
      "affiliations": [
        "Department of Tumor Pathology, Graduate School of Health Sciences, Kumamoto University, Kumamoto, Japan"
      ],
      "name": "Hiromu Yano"
    },
    {
      "affiliations": [
        "Department of Pathology, Toranomon Hospital, Minato, Tokyo, Japan"
      ],
      "name": "Keiichi Kinowaki"
    },
    {
      "affiliations": [
        "Department of Medical Oncology, Toranomon Hospital, Minato, Japan"
      ],
      "name": "Kohji Takemura"
    },
    {
      "affiliations": [
        "Department of Medical Oncology, Toranomon Hospital, Minato, Japan"
      ],
      "name": "Keita Uchino"
    },
    {
      "affiliations": [
        "Department of Urology, Yokohama City University, Yokohama, Japan"
      ],
      "name": "Hisashi Hasumi"
    },
    {
      "affiliations": [
        "Department of Cell Pathology, Graduate School of Medical Sciences, Kumamoto University, Kumamoto, Japan"
      ],
      "name": "Yoshihiro Komohara"
    }
  ],
  "title": "Complete response to immune checkpoint blockade in sarcomatoid renal cell carcinoma with bone marrow metastasis: case report with tumor immune microenvironment profiling",
  "uid": "b764eb5a-51be-57a2-8b33-17c37d8b5f5e"
}