PDX CORE PROJECT SUMMARY The goals of the patient-derived xenograft (PDX) Development and Trial Center (PDTC) PDX Core are to establish and maintain PDX lines for the purpose of conducting animal preclinical trials using experimental and standard-of-care therapeutics; to promote quality-control, reproducibility, and collaboration by developing and maintaining shared Standard Operating Procedures (SOPs) for PDX development, maintenance, experimentation, and pathogen testing; to provide infrastructure to manage large PDX collections and to generate, store, and manage PDX-based experimental data generated by the projects; to facilitate exchange of PDX models between the PDXNet program; and to facilitate transfer of experimental data to the PDTC Biostatistics and Bioinformatics Core and the PDTC PDXNet Data Commons and Coordinating Center to relate treatment responses to the molecular characteristics of individual patients’ tumors. Our PDTC PDX Core current comprises 162 breast PDX lines available for projects within our PDTC Center and across the PDXNet program.