Inclusion Criteria:

   - Histologically confirmed adenocarcinoma of the prostate from a prostate biopsy.

   - 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 cancer diagnosis cannot be more than 3 years prior to baseline visit date.

   - No more than two prostate biopsies including the initial biopsy in which cancer was
   diagnosed.

   - If cancer diagnosis is more than one year before enrollment, there must be two
   prostate biopsies including the initial biopsy in which cancer was diagnosed and a
   subsequent biopsy. The subsequent biopsy may occur on the same day as the baseline
   visit.

   - Biopsies must have at least 10 cores.

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.