 Investigators have two straightforward primary objectives for this pilot study. First we will establish the background levels of modified DNA in individuals with no history of prostate cancer. Second, investigators will quantify cancer-specific methylated DNA in men with known high risk prostate cancer. Investigators will begin by collecting urine and plasma specimens from normal volunteers. In parallel investigators will collect specimens for quantitation of cancer-specific DNA modifications in men with known high-risk prostate cancer receiving standard treatment in the Department of Radiation Oncology. Patient samples will be collected at multiple time points before, during, and after radiation treatment and then will be subjected to careful DNA sequencing and analysis. This will allow investigators to simultaneously characterize and quantify prostate cancer specific DNA occurring anywhere in the genome, thereby allowing investigators to predict which patients have prostate cancer still present in their body after treatment even if the PSA is very low or undetectable. If successful, this project will be an important first step in the development of a noninvasive test to track disease burden and therapeutic response during and after radiation therapy for high-risk prostate cancer. 