PROJECT SUMMARY/ABSTRACT OMRF operates three mouse barrier facilities with the only germ-free mouse facility (GFM) and patient-derived xenograft core (PDX) in Oklahoma. The research programs of all five Research Project Leaders (RPLs) on this new COBRE use mouse models, which make up approximately 15% of the daily mouse population of the OMRF mouse facilities. As these investigators grow their research programs in the next five years, this percentage is expected to increase to ~22%. In addition, the laboratories of the CMRO COBRE mentors also utilize mouse models, and the mentors and RPLs combined currently constitute almost 60% of the census. Reliable sterilization of mouse caging and ancillary equipment is essential for mouse barrier facilities, especially those housing immunodeficient and germ-free mice. OMRF?s current sterilizer is 20 years old and is failing. To address this, OMRF plans to replace the failing sterilizer and add a second sterilizer for future expansion. This supplement requests partial support of the sterilizing equipment. OMRF will provide 50% of the total cost for this equipment. The requested equipment is critical for reproducible results for research of the CMRO COBRE RPLs and their mentors as well as animal health and well-being. Additionally, this equipment will also benefit other COBRE and COBRE-eligible investigators from additional institutions in Oklahoma (University of Oklahoma Health Sciences Center and Oklahoma State University), as the GFM and PDX facilities are not found elsewhere in the state.