 In this pilot study, we propose to address the question: is there a small peptide mass proteomic profilepattern in blood that can distinguish men with a clinically insignificantlatent prostate cancer from men with more advanced pathological features? We will obtain a pre-operative blood sample from men with clinically localized prostate cancer undergoing radical prostatectomy and determine their preoperative small peptide mass proteomic profile. The pathological features of the radical prostatectomy will be determined and the patient will be classified as having either a pathologically insignificantlatent prostate cancer or a significant cancer. We will then analyze whether or not the small peptide mass proteomic profile in blood can distinguish these groups before radical prostatectomy. In addition, each of these patients will have a blood sample collected at least 6 weeks to 12 months after surgery to evaluate and compare changes that occur as a result of radical prostatectomy. This will determine the effect of radical prostatectomy on the small peptide mass proteomic profile in blood and determine if the proteomic profiles in blood collected prior to radical prostatectomy can identify men at increased risk for recurrence. 