{
  "abstract": "Background Immune checkpoint inhibitors such as pembrolizumab offer a therapeutic option for head and neck squamous cell carcinoma (HNSCC), yet only a minority of patients benefit. Although PD-L1 expression and the combined positive score (CPS) are used as biomarkers for patient selection, they poorly predict clinical response. There is a critical need to identify more robust, spatially-informed biomarkers that better capture the complexity of the tumor immune microenvironment (TME).Methods We analyzed tumor samples from 48 HNSCC patients prior to pembrolizumab treatment using FAST (fast cyclic immunofluorescence), a rapid multiplexed imaging platform. Whole-tissue sections were profiled for 21 protein markers across 6,316 fields of view, capturing nearly 3 million single cells. Computational pipelines were applied to segment, classify, and spatially map immune and tumor cell types. We quantified PD-L1 expression, cellular densities, and spatial interactions, and developed multiparametric spatial scores (MPSSs) to model predictors of treatment response and survival.Results PD-L1 expression, whether assessed by clinical CPS or enhanced single-cell profiling, showed limited correlation with treatment response. Spatial analysis revealed that the abundance and clustering of CCR7 +dendritic cells (DCs)—particularly in the tumor periphery—were significantly associated with therapeutic response and overall survival. These CCR7+ DCs often colocalized with T cells and macrophages, forming immune niches. Modeling revealed that MPSSs incorporating spatial metrics of CCR7+ DC density, clustering, and proximity to T cells outperformed single-feature metrics and CPS in predicting patient outcomes.Conclusions This study demonstrates that spatial organization of the TME, particularly CCR7 + DC niches, is a promising predictor of immunotherapy benefit in HNSCC. These findings highlight the value of high-resolution spatial profiling for biomarker discovery and suggest that CCR7+ DC clusters may serve as actionable biomarkers for response stratification in HNSCC and potentially other cancers.",
  "authors": [
    {
      "affiliations": [
        "Massachusetts General Hospital, Boston, MA, USA"
      ],
      "name": "Juhyun Oh"
    },
    {
      "affiliations": [
        "University of Bern, Bern, Switzerland"
      ],
      "name": "Jan Hoelzl"
    },
    {
      "affiliations": [
        "Massachusetts General Hospital, Boston, MA, USA"
      ],
      "name": "Jonathan CT Carlson"
    },
    {
      "affiliations": [
        "University of Bern, Bern, Switzerland"
      ],
      "name": "Ruben Bill"
    },
    {
      "affiliations": [
        "Massachusetts General Hospital, Boston, MA, USA"
      ],
      "name": "Hannah M Peterson"
    },
    {
      "affiliations": [
        "Massachusetts General Hospital, Boston, MA, USA"
      ],
      "name": "William C Faquin"
    },
    {
      "affiliations": [
        "University of Lausanne, Lausanne, Switzerland",
        "University of Geneva, Geneva, Switzerland",
        "Ludwig Institute for Cancer Research, Lausanne, Switzerland",
        "AGORA Cancer Research Center, Lausanne, Switzerland"
      ],
      "name": "Mikael Pittet"
    },
    {
      "affiliations": [
        "Yale University School of Medicine, New Haven, CT, USA"
      ],
      "name": "Sara Pai"
    },
    {
      "affiliations": [
        "Massachusetts General Hospital, Boston, MA, USA",
        "Harvard Medical School, Boston, MA, USA"
      ],
      "name": "Ralph Weissleder"
    }
  ],
  "title": "93 Spatial analysis of head and neck squamous cell cancer tumor microenvironment identifies predictors of pembrolizumab therapy",
  "uid": "933f521f-dd91-5dee-a660-b19ae69f5de6"
}