1519Background: Angiosarcoma (AS) is a rare soft tissue sarcoma, with an incidence of 300/yr and a 5-year DSS of 30%. The low incidence has impeded large-scale research efforts that may lead to improved clinical outcomes. To address this, we launched a nationwide study, which seeks to empower patients (pts) to accelerate research by sharing their samples and clinical information remotely. Methods: With pts and advocacy groups we developed a website to allow AS pts to participate across the US. Pts are mailed a saliva and blood draw kit for germline and cell free (cf) DNA analysis. We then obtain medical records and stored tumor samples. Whole exome sequencing will be performed on tumor, cfDNA and saliva samples. Transcriptome analysis will be performed on tumor samples. A clinically annotated genomic database will be generated and shared widely to identify genomic drivers and mechanisms of response and resistance to therapies. Study updates will be shared with pts regularly. Results: We conducted a 3-week...