ABSTRACT ? Biospecimen Unit The breast Precancer Atlas (B-PCA) will elucidate the imaging, molecular, and microenvironment differences that influence evolution and ecology of the tumor and are associated with invasive cancer progression. The objective of the Biospecimen Unit is to collect retrospective and prospective tissue samples of DCIS from which to construct the Atlas, selecting those cohorts and cases which are likely to be most informative for Atlas construction. The Biospecimen Unit of the B-PCA will be responsible for properly, reliably, and efficiently executing all aspects of sample collection, while ensuring alignment with the overall scientific goals of the project. The Unit will oversee all procedures related to specimen acquisition, storage, tracking, and distribution to support the activities of the B-PCA investigators. The Biospecimen Unit is comprised of 3 primary sites (Duke, Stanford, and Washington University) which will each manage specimen acquisition in accordance with individual institutional procedures. In addition, there will be virtual centralized coordination of all B-PCA activities related to specimen annotation and distribution. The Biospecimen Unit will coordinate shared resources, including multicenter case-control matched sets of DCIS collected through Washington University, the Translational Breast Cancer Research Consortium (TBCRC), and prospective clinical trial samples from COMET, an active surveillance study for low risk DCIS. Integration between the Characterization and Data Analysis Units of the B- PCA will be promoted by the shared data infrastructure, including access to metadata to facilitate sharing of samples and data. Processes and procedures around specimen collection, sample annotation, and tissue distribution will be governed through shared SOPs, MTAs/DUAs and harmonized IRB protocols. The overarching goals of the Biospecimen Unit are: 1) to create the organizational structure and processes necessary to support these activities, and 2) to use this infrastructure to collect, track, and distribute samples, based upon the needs of the B-PCA investigators. The structure of the Biospecimen Unit has been designed to be flexible and scalable in order to accommodate future collaboration around specimen collection and sample characterization across the PCA centers and the HTAN.