Abstract 1: Synapse.org as a foundational platform supporting multicenter cancer data coordination, benchmarking, and broad community reuse.

Abstract Collaborative cancer research requires a shared data infrastructure that functions across institutions, modalities, and funders. Synapse.org, developed by Sage Bionetworks, is a versatile public data platform used by research consortia, real-world data efforts, and computational challenges. We describe the use of Synapse to support diverse cancer research communities. Synapse provides tools for validated metadata, provenance, versioning, and fine-grained access control. For supported communities we provide curation and validation apps, domain-specific portals, dashboards, and challenge frameworks. APIs and clients connect Synapse to local compute and trusted research environments (Cavatica, Terra, Pluto, SevenBridges CGC) via GA4GH DRS. Recent enhancements include human-guided, AI-powered curation, OpenSearch-based discovery, and natural-language data search. Data arrive through contributor uploads (web, CLI, APIs), programmatic ETL pipelines, and indexing of external repositories (GEO, dbGaP).. Curated datasets are indexed for discovery and surfaced through program portals. Community use and feedback guide curation priorities, maintaining a continuous improvement cycle. The Synapse platform hosts 3.6 PB data used by 6,000 monthly users. The Cancer Complexity Knowledge Portal links 160 grants, 4,178 publications, 1,039 datasets, and 321 tools focused on cancer biology. The Human Tumor Atlas Network DCC manages 334 TB of harmonized omics data (0.23M files from 2,372 cases and 11,378 biospecimens across 60 diseases and 25 assays), with 2,500 annual users. The NF Data Portal integrates over 200 TB data from 312 neurology and oncology studies, and catalogues 1,100 tools spanning NF1, NF2, and schwannomatosis. As part of the coordinating center for AACR Project GENIE we have supported the ETL and sharing of clinico-genomic data from 19 centers, including 211,527 patients and 250,018 samples. DREAM cancer challenges run on Synapse have established benchmarks including in AML subtyping, prostate cancer survival, immunotherapy response and digital mammography. Independent Synapse users have contributed 1.2M public files (95 TB) across 400+ cancer-related projects. A user-friendly generalist data platform and a set of proven data coordination and challenge operations lower the activation energy for new cancer collaborations, from independent projects to large, multi-institutional networks. We invite researchers to explore Synapse.org and our data portals. AI was used to summarize metrics and refine wording Authors reviewed and approved all content. Citation Format: Adam Taylor, Gaia Andreoletti, Robert Allaway, Jineta Banerjee, Orion Banks, Angie Bowen, Kevin Boske, Aditi Gopalan, Ashley Clayton, Xindi Guo, Savitha Sangameswaran, Amber Nelson, Aditya Nath, Milen Nikolov, Anh Nguyet Vu, Ziwei Pan, Alex Paynter, Chelsea Nayan, Thomas Yu, Bishoy Kamel, Serghei Mangul, Alberto Pepe, Luca Foschini, Susheel Varma. Synapse.org as a foundational platform supporting multicenter cancer data coordination, benchmarking, and broad community reuse abstract. In: Proceedings of the American Association for Cancer Research Annual Meeting 2026; Part 1 (Regular Abstracts); 2026 Apr 17-22; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2026;86(7 Suppl):Abstract nr 1.