Blood samples are collected at baseline and on the day of prostatectomy or brachytherapy. Samples are analyzed for testosterone and 5-α-dihydrotestosterone levels by capillary gas chromatography-mass spectrometry; genetic polymorphisms in the type 2 5-α reductase gene by PCR and sequencing analyses; and selenium levels by atomic absorption spectrophotometry. Additional blood samples will be stored for future analysis of alpha and gamma tocopherol, lycopene, and other vitamin levels. Toenail samples are also collected to provide an indicator of long-term selenium status. Prostate tissue samples are collected during and after prostatectomy or prior to brachytherapy. Samples are analyzed for expression of biomarkers (e.g., prostate-specific antigen, kallikrein 2, and NKX 3.1) by quantitative RT-PCR and apoptosis by TUNEL assay, immunohistochemistry, and ELISA.