ADMINISTRATIVE SUPPLEMENT ABSTRACT This application is being submitted in response to NOT-CA-19-029. This application requests supplemental funding to leverage existing resources including location data for fresh food outlets, rurality, and socioeconomic status (SES) to address the role of built and social environmental factors on prostate cancer aggressiveness (in support of Aim 1 of the parent grant). We will examine previously identified etiological factors (e.g. folate/folic acid intake, DHFR polymorphism) in connection with geospatial access to fresh food using a multi-level logistic regression model. We hypothesize individuals with greater geospatial access to fresh foods will have higher dietary intake of folate and a corresponding reduced likelihood of high-aggressive prostate cancer, modified by the DHFR polymorphism. We propose the following supplemental aims: 1) examine the association between geospatial accessibility to fresh food outlets and dietary intake of folate among EAs and AAs, and 2) evaluate the multilevel association of geospatial accessibility to fresh food outlets, socioeconomic status, and prostate cancer aggressiveness in EAs and AAs. The proposed supplement will expand and enhance Aim 1 of the parent grant to investigate not only individual-level dietary factors, but also the role of the social and built environment on prostate cancer aggressiveness and provide greater insight into the complex nature of prostate cancer etiology. Successful completion of the proposed supplemental aims will help identify modifiable risk factors at multiple scales, strengthening the impact of the parent grant and providing a valuable resource for the broader scientific community.