16.0 Abstract: Flow Cytometry Shared Service The Flow Cytometry Shared Service (FCSS) provides investigators at the University of Maryland Marlene and Stewart Greenebaum Comprehensive Cancer Center (UMGCCC) with essential services that support research in immunology and cancer biology requiring flow cytometry and with analytical (spectral and mass cytometry) and cell sorting capabilities. FCSS provides convenient access to cost-effective and high-quality services managed by expert staff. FCSS was the first facility in the Baltimore/Washington area with both mass and spectral cytometry instrumentation. The two Helios mass cytometers enable simultaneous measurement of large numbers of parameters (currently >50 parameters/cell) with minimum compensation. Using the new- generation Cytek Aurora spectral cytometers, FCSS has developed in-house 23- and 30-color immunophenotyping plug-and-play use panels. The MoFlo Astrios advanced cell sorter provides the ability to simultaneously sort six populations under BSL-2 containment. A Miltenyi MACSQuant Analyzer 10 is housed in this space which is only accessible to FCSS staff and is used to analyze clinical samples for CAR-T cell therapy developed in our Fannie Angelos GMP Laboratory for Cellular Therapeutics. These state-of-the-art instruments offer innovative approaches to study immunology and cancer biology and to monitor novel clinical trials. FCSS is staffed by technical experts with decades of experience in the operation of flow cytometers/sorters and mass cytometers. The monthly lectures presented by the FCSS director are attended by nearby members of academic institutions, hospitals, and biotech companies, and the lectures are widely considered a great educational resource. An internal scientific advisory board consisting of FCSS users provides guidance to FCSS and helps develop strategic planning for new equipment and technologies. FCSS provides easy access to flow cytometry services. Cancer Center investigators with peer-reviewed funding are prioritized. FCSS services are highly cost-effective, as the fee structure is competitive with other academic and commercial sources, and a 25% UMGCCC-funded subsidy is given to Cancer Center members. FCSS is highly utilized. In 2019, FCSS supported studies by 90 total investigators, 42 (46.7%) of whom were UMGCCC members. FCSS supported $62.4 million of total funding. $27.3 million of this funding was cancer-related, all of which was peer reviewed. FCSS supported 213 cancer-related publications from 2015 to 2019, including those published in such high-impact journals as PNAS, Nature, and Nature Communications.