Inclusion Criteria:

          1. Male age between 50-85

          2. Diagnosed with prostate cancer or high-grade PIN within the last 24 months through the
             most recent biopsy; or patients who have a total PSA level above 4.0 but have not been
             diagnosed with prostate cancer yet

          3. Has not received any prostate cancer therapy including surgery, chemotherapy, hormone
             therapy, or radiation therapy

          4. Clinical Gleason score of the tumor is ≤6 for patients ≤70 years or ≤7 for >70 years;
             (non-applicable for non-cancer patients with elevated PSA or high-grade PIN)

          5. The clinical stage of the cancer is T1c or below (non-applicable for non-cancer
             patients with elevated PSA or high-grade PIN)

          6. The patients have been recommended for and placed under active surveillance without
             immediate treatment

          7. Able to provide written informed consent

        Exclusion Criteria:

          1. Patients taking mushroom (including reishi) or other herbal products/natural
             supplements

          2. Patients with a known allergy to mushrooms

          3. Prisoners

          4. Patients who receive treatment with 5-alpha reductase inhibitors (finasteride
             [Propecia®, Proscar®,], or dutasteride [Avodart®) within 28 days prior to
             randomization are not eligible. The use of these drugs is not allowed during the
             patients' study participation.

          5. Patients with a history of non-cutaneous malignancy in the previous 5 years are not
             eligible.

          6. Patients taking warfarin, heparin, Aspirin >81mg/day, or other prescribed blood
             thinners: Reishi may increase the risk of bleeding.

          7. Patients with platelets levels below 139 X 103/ul or history of bleeding disorders

          8. Patients undergoing chemotherapy: Reishi may make some chemotherapy drugs less
             effective.

          9. Patients with any known immune disorder, including but not limited to HIV or other
             primary or secondary immune deficiency diseases, autoimmune diseases, history of or
             being considered for organ transplants, etc.

         10. Patients taking immunosuppressants (Corticosteroids, Calcineurin inhibitors, mTOR
             inhibitors, IMDH inhibitors, Biologics, Monoclonal antibodies): Reishi can stimulate
             immune responses.

         11. Patients taking cytochrome P450 2E1, 1A2, and 3A sensitive substrate drugs: Reishi may
             increase the risk of side effects of these drugs.

         12. Patient has total bilirubin >1.5 MG/DL, alanine aminotransferase (ALT) >51 U/L or
             aspartate aminotransferase (AST) >46 U/L.