The Radiation and Free Radical Research Core focuses on providing state of the art technologies to HCCC investigators studying the role of oxidative stress and redox biology as they relate to cancer biology and cancer therapy. There is growing evidence that oxidative stress and redox biology are critical determinants of cancer biology including the processes of initiation, promotion, and progression to malignancy as well as the prevention and treatment of cancer. The Radiation and Free Radical Research Core (RFRRC) was established to provide easy access to free radical and radiation biology expertise, reagents, technologies, and analysis for HCCC investigators doing basic, pre-clinical, and clinical research. The three basic services provided by the core are: 1) Ionizing radiation services and phosphorimaging as well as cell cycle analytical tools critical to understanding cellular responses to radio-chemo-therapy. 2) Electron paramagnetic resonance spectroscopy and other detection methodologies for measuring free radicals, singlet oxygen, nitric oxide and the array of related oxidants and oxidative damage products. 3) Antioxidant enzyme services to provide easy access to technologies for modifying and measuring molecules responsible for pro-oxidant formation, metabolism of reactive oxygen species, and mediators of redox biology including: anti-oxidant proteins, small molecular weight cellular thiols and reductants, as well as redox mediated signaling and gene expression pathways governing growth, differentiation, and cell injury processes. The RFRRC is unique in its ability to provide HCCC members easy access to such knowledge, reagents and resources. The expertise for the RFRRC is based in the Free Radical Cancer Biology Program, but the RFRRC had more than 80 HCCC members use its facilities from 2005-2009, representing all 6 HCCC programs. During this period of support the research activities facilitated by the services in the RFFRC significantly contributed to 135 peer reviewed publications.