Abstract 4859: A novel sarcoma tumoroid platform preserving the tumor microenvironment to guide personalized immunotherapy

Abstract Sarcomas are rare, aggressive mesenchymal cancers with over 80 subtypes. Although they represent a small fraction of adult cancers, sarcomas comprise over 20% of pediatric solid tumors and carry poor outcomes for patients with advanced disease. Preclinical modeling remains challenging: traditional 2D cultures fail to preserve the tumor microenvironment (TME), while conventional 3D organoid platforms rely on enzymatic dissociation, which disrupts cellular interactions essential for TME integrity. Patient-derived xenografts, though more representative, are costly and low-throughput. To address these limitations, this study aims to develop reproducible 3D sarcoma tumoroids as a translational platform for functional studies and therapeutic testing that preserves the TME.Freshly resected sarcoma specimens were mechanically cut into small fragments without enzymatic dissociation, preserving the TME in each fragment, and cultured in suspension or matrix-embedded conditions. Media formulations and growth factor combinations were evaluated across sarcoma subtypes to optimize culture performance. Tumoroid formation and growth were monitored for 14 days using brightfield microscopy, quantitative area analysis, and alamarBlue viability assay. Structural integrity and TME preservation were assessed by hematoxylin and eosin (H Part 1 (Regular Abstracts); 2026 Apr 17-22; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2026;86(7 Suppl):Abstract nr 4859.