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Abstract BAP1 mutations are associated with increased T cell and tumor-associated macrophage infiltration in clear cell renal cell carcinoma (ccRCC) and are predictive of poor prognosis. BAP1 mutations have also been found to be associated with T-cell infiltration in peritoneal mesothelioma and uveal melanoma. Because BAP1 mutations are known to be associated with aggressive disease and poor survival, we hypothesize that these mutations lead to a more immunosuppressive microenvironment. Using single nucleus RNA sequencing and high-resolution spatial transcriptomics, we confirmed that BAP1 mutant tumors are immune hot with a high fraction of Treg, exhausted CD8+ T cells, CD4+ T cells, and macrophages. At the same time, these tumors have a lower proportion of endothelial cells and pericytes. Evident of pro-tumor microenvironment we have found BAP1 mutations to be associated with the upregulation of SPP1, CD163, and MARCO immunosuppressive genes in tumor-associated macrophages. Here we propose a mechanism by which BAP1-mutant cancer cells induce an immunosuppressive microenvironment: through activation of the complement system and TGF-β signaling to attract macrophages. Taken together, our results suggest that BAP1 mutations contribute to poor ccRCC outcomes not only through cell-intrinsic effects, but also by promoting infiltration of Tregs and tumor-associated macrophages and polarizing infiltrated macrophages towards immunosuppressive phenotype. Citation Format: Ilya Strunilin, Wagma Caravan, Atieh Abedin-Do, Andrew Houston, Yize Li, Yizhe Song, Song Cao, Chia-Kuei Mo, Siqi Chen, Russel Pachynski, Feng Chen, Li Ding. Single cell resolution spatial transcriptomics reveals genetic driver and TME interaction in clear cell renal cell carcinoma abstract. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts) ; 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84 (6Suppl): Abstract nr 5367.
Strunilin et al. (2024) studied this question.