The Pathology and Tissue Informatics Core (PTIC) is essential for the success of the Vanderbilt Breast Cancer SPORE. The goal of the PTIC is to facilitate the clinical and translational research aims of this renewal application via three primary missions: 1) To provide human tissue and body fluid collection, processing and quality control according to standardized protocols by trained personnel; 2) To provide specialized technical and diagnostic histo-pathology services in human and mouse tumors including expertise in performance and interpretation of immunohistochemistry (IHC), immunofluorescence (IF), and fluorescence in situ hybridization (FISH) assays, diagnostic and cellularity assessments on all procured tissue used for correlative studies, and construction of tissue microarrays; and 3) To provide high-quality and efficient informatics support for collection, pathological and clinical annotation, tracking and distribution of breast tissues for translational research. The core is co-directed by an expert breast pathologist and the Vanderbilt Ingram Cancer Center (VICC) Director of Clinical Informatics who oversees the development and maintenance of the clinical research information systems. All tissue is collected from patients with breast cancer consented for enrollment into SPORE and VICC protocols or under the auspices of the Vanderbilt Breast Tissue and Body Fluids Repository. The Repository, established in the initial funding period of this Breast SPORE, is now a robust collection of over 25,000 tissue, blood and urine samples, available to Breast SPORE investigators, which are linked to clinical data through the Breast SPORE Database. The core provides best practices oversight of optimal tissue utilization for each tissue specimen enabling numerous correlative studies such as gene arrays, sequencing and IHC to be performed on small tumor samples. The core will be directly involved in the analysis of these studies and will interact extensively with all the projects. The PTIC provides a centralized mechanism for performance of specialized technical and diagnostic histo- pathology services, critical to the success of the Breast SPORE, preventing the inefficiencies of tissue acquisition by individual projects and the performance of tissue-based assays by inexperienced hands.