The purpose of this study is to determine the effects of Mikei® Red Reishi Essence EX, a natural supplementary dietary product, on the immune function of prostate cancer patients and patients with non-cancerous conditions of the prostate. According to limited published scientific research and clinical studies, Reishi mushroom extract may support the body's immune function. According to cancer immunology research, at early stage of tumor development, the immune system can mount defensive actions to eliminate or inhibit tumor growth. This study is to examine the specific effect of Mikei® Red Reishi Essence EX on the immune function of prostate cancer patients and patients with non-cancerous conditions of the prostate.