Inclusion Criteria:

   - Histologically confirmed adenocarcinoma of the prostate.

   - Clinically localized prostate cancer: T1-2, NX or N0, MX or M0.

   - No previous treatment for prostate cancer (including hormonal therapy, radiation
   therapy, surgery, or chemotherapy).

   - ECOG Performance Status 0 or 1.

   - Patient has elected Active Surveillance as preferred management plan for prostate
   cancer.

   - Patient consent has been obtained according to local Institutional Review Board for
   acquisition of research specimens.

   - Patient is accessible and compliant for follow-up.

   - Prostate biopsy requirements:

      1. If diagnosis was within one year of baseline visit, participant must have at
      least one biopsy with at least 10 cores.

      2. If diagnosis was more than 1 year prior to baseline visit, participant must have
      a minimum of 2 biopsies, one of which must be within 2 years prior to baseline
      visit.

Exclusion Criteria:

   - Unwillingness or inability to undergo serial prostate biopsy.

   - History of other malignancies, except: adequately treated non-melanoma skin cancer or
   adequately treated superficial bladder cancer (Ta) or other solid tumors curatively
   treated with no evidence of disease for > 5 years.