Core B – Biospecimen Core: Summary/Abstract: The projects of this LMS SPORE will use leiomyosarcoma (LMS) biospecimens for translational research. A key function of this Core will be ensuring the accuracy of diagnosis of LMS. To that end, Jason Hornick, MD, PhD, an expert sarcoma pathologist, will Co-Direct the Biospecimen Core along with Nilsa Ramirez, MD, an expert in biospecimen repositories and banking. The functions of the Biospecimen Core will include pathology review, biospecimen procurement from the institutions participating in the LMS SPORE clinical studies, basic and specialized processing, management of biospecimen-related data, and distribution of biospecimens and data to project investigators. Biospecimens collected for this LMS SPORE will be prioritized to distribute to the LMS SPORE investigators for the defined projects. After the needs of the planned research have been addressed, residual banked biospecimens can be distributed to other investigators using existing mechanisms established by the Administrative Core/MPI of this LMS SPORE. The Biospecimen Core will provide the latest biorepository-based technological innovations and best practices, resulting in constant improvements in operational capabilities, investigator access to biospecimens, and the stewardship of these precious resources. Dr. Nilsa Ramirez, who has extensive experience in the management of biospecimen quality control, processing, and banking, will oversee all activities of the Biospecimen Core and will provide guidance to the Project leaders regarding biospecimen best practices. Dr. Hornick will oversee the review of pathology and histology assessments to confirm diagnosis of all cases of LMS and will be the arbiter in case of discrepancy in the diagnosis. The Biospecimen Core will work closely with the Administrative Core and the project leadership to ensure the success of the planned research. The collaborative nature of this LMS SPORE is necessary for the study of this subtype of rare malignancies, where only multi-institutional cooperation can facilitate the acquisition of sufficient biospecimen resources vital to make progress. The biospecimens banked in the Biospecimen Core will provide an essential resource for the LMS SPORE team as well as future investigators.