This is an open label, single institution, pilot study of rituximab neoadjuvant therapy in patients with high risk prostate cancer scheduled to undergo radical prostatectomy. Prior to prostatectomy, patients will receive one treatment cycle (28 days) of rituximab 375 mg/m2 intravenously once weekly. Patients will be scheduled to undergo radical prostatectomy within two weeks of completing study treatment. Tissue from prostatectomy will be used for immunohistochemistry (IHC) staining of pharmacodynamic markers.