Prostate cancer is the most prevalent cancer in the Western male population and the second leading cause of cancer death in men, affecting over 10 million individuals. Present approaches to control the cancer mortality have focused on the detection of the cancer at early stages when it is still locally confined and may be curable. Identification of the prostate-specific antigen (PSA) has facilitated the early diagnosis of prostate cancer. However, PSA has limited specificity and sensitivity in appropriately detecting early stages of abnormal prostate growth. PSA levels fail to differentiate between indolent and aggressive cancers, do not correlate with tumor size, and cross-react with other serine proteases namely, glandular kallikreins 1 and 2. Besides cancer, its levels also increase in men with benign prostatic hyperplasia (BPH), prostatitis, and other non-malignancies. Additional prostate-specific genes and metabolites need to be identified to provide a better understanding of the molecular mechanisms of prostate physiology and pathophysiology. Novel markers for the diagnosis and development of new treatment modalities are urgently needed.