Related Terms

• A beta-1,4-glucan, basidiomycetes, basidiomycotinae, biological response modifier, Boletus versicolor, BRM, cloud mushroom, Coriolus versicolor, Kawaratake, Kayken Caps®, Krestin®, Polyporaceae, Polyporus versicolor, polysaccharide K, polysaccharide Kureha, Polystictus versicolor, protein-bound B-glucan, proteoglycans, PSP, Saru-no-koshikake, strain CM-101, turkey tail mushroom, Trametes versicolor, yun zhi.

Background

• Protein-bound polysaccharide (PSK) has been used in traditional Chinese medicine (TCM) since the Ming Dynasty of China.

• In the 1980s, the Japanese government approved the use of PSK for treating several types of cancers. By 1984, it ranked 19th on the list of the world's most commercially successful drugs with annual sales of $255 million.

• PSK is obtained from cultured mycelia of the Coriolus versicolor, a mushroom thought to have antimicrobial, antiviral, and antitumor properties.

• PSK extracts are available for clinical use in Japan, where it is widely used for cancer immunochemotherapy. In Japan, PSK is currently used as a cancer treatment, in conjunction with surgery, chemotherapy, and/or radiation. Its active ingredient can be administered as a tea or in oral capsule form. In the United States, a similar product is labeled simply Coriolus versicolor extract. Coriolus versicolor is available in limited supply in U.S. markets. In Japan, PSK is currently the best-selling cancer medicine.

Scientific Evidence

Tradition/Theory

The below uses are based on tradition or scientific theories. They often have not been thoroughly tested in humans, and safety and effectiveness have not always been proven. Some of these conditions are potentially serious and should be evaluated by a qualified health care professional.

• AIDS, antibacterial, antifungal, antioxidant, antiviral, atherosclerosis (hardening of the arteries), cancer prevention, hepatic disorders, herpes, HIV, immunomodulator, infections, kidney disease prevention, liver protection, pancreatic cancer, post-surgical recovery, stamina, strength.

Dosing

The below doses are based on scientific research, publications, traditional use, or expert opinion. Many herbs and supplements have not been thoroughly tested, and safety and effectiveness may not be proven. Brands may be made differently, with variable ingredients, even within the same brand. The below doses may not apply to all products. You should read product labels, and discuss doses with a qualified healthcare provider before starting therapy.

Adults (over 18 years old)

• Safety and efficacy has not been proven for any dose. When taken by mouth, 3 grams of PSK has been used daily or every other day, either alone or with conventional therapy. 1 gram, three times daily of PSK for one month, has been used for the treatment of a tumor. PSK has also been administered at a dose of 2-3 grams/meter2 daily in three divided doses for one month.

Children (under 18 years old)

• There is not enough evidence available to recommend the use of PSK in children.

Safety

The U.S. Food and Drug Administration does not strictly regulate herbs and supplements. There is no guarantee of strength, purity or safety of products, and effects may vary. You should always read product labels. If you have a medical condition, or are taking other drugs, herbs, or supplements, you should speak with a qualified healthcare provider before starting a new therapy. Consult a healthcare provider immediately if you experience side effects.

Allergies

• Avoid in individuals with a known allergy/hypersensitivity to PSK, Coriolus versicolor, or any of its constituents.

Side Effects and Warnings

• PSK generally seems to have a low incidence of mild and tolerable side effects. In one report, three cases of toxicity were noted, and PSK was discontinued. PSK has been associated with side effects of gastrointestinal upsetand darkening of the fingernails, but these effects have been limited and general safety has been demonstrated with daily oral doses for extended periods. Darkening of the fingernails and coughing have been reported during the administration of the powder drug.

• Low blood cell counts including leukopenia, thrombocytopenia, and albuminuria (protein in the urine) were observed in two clinical trials. It should be noted that patients also received chemotherapy in addition to PSK in these trials, which may have contributed.

• Use cautiously in patients with coronary artery disease due to antiangiogenic properties (inhibition of new blood vessel growth) in the heart.

Pregnancy and Breastfeeding

• Not recommended due to lack of sufficient data.

Interactions

Most herbs and supplements have not been thoroughly tested for interactions with other herbs, supplements, drugs, or foods. The interactions listed below are based on reports in scientific publications, laboratory experiments, or traditional use. You should always read product labels. If you have a medical condition, or are taking other drugs, herbs, or supplements, you should speak with a qualified healthcare provider before starting a new therapy.

Interactions with Drugs

• Liver function impairment and toxicity has been reported. Caution is advised when taking PSK with other agents that are broken down by the liver due to increased risk of side effects.

• Antiangiogenic properties (inhibition new blood vessel growth) have been proposed. In theory, there could be an additive effect when PSK is taken in conjugation with other known antiangiogenic agents, such as leflunomide.

• Thrombocytopenia (low blood platelet count) has been reported. Theoretically, this could increase the risk of bleeding. Leukopenia and albuminuria were also observed in two clinical trials. It should be noted that patients also received chemotherapy in addition to PSK in these trials. These effects may be attributed to either PSK or chemotherapy.

• Numerous animal and human studies have demonstrated that PSK may improve survival time in patients with lung cancer, gastric cancer, stomach cancer, colon cancer, and leukemia when used in conjunction with chemotherapy. This may be a positive interaction, although additional study is needed to confirm this finding.

• PSK in immunochemotherapy has been used in combination with hormone therapy to treat pancreatic cancer; therefore, additive effects are possible.

Interactions with Herbs and Dietary Supplements

• Liver function impairment and toxicity has been reported. Caution is advised when taking PSK with other agents that are broken down by the liver due to increased risk of side effects.

• Antiangiogenic properties (inhibition of new blood vessel growth) have been proposed. In theory, there could be an additive effect when PSK is taken in conjugation with other known antiangiogenic herbs and supplements such as shark cartilage, horse chestnut, feverfew, and bilberry.

• Thrombocytopenia (low blood platelet count) has been reported. Theoretically, this could increase the risk of bleeding. Leukopenia and albuminuria were also observed in two clinical trials. It should be noted that patients also received chemotherapy in addition to PSK in these trials. These effects may be attributed to either PSK or chemotherapy.

• PSK in immunochemotherapy has been used in combination with hormone therapy to treat pancreatic cancer; therefore, additive effects are possible.

• Theoretically, PSK may have a synergistic effect with other immunotherapeutic herbs and supplements. Numerous animal and human studies have demonstrated PSK improves survival time in patients with lung cancer, gastric cancer, stomach cancer, colon cancer, and leukemia when used in conjunction with chemotherapy.

Author Information

• This information is based on a systematic review of scientific literature edited and peer-reviewed by contributors to the Natural Standard Research Collaboration (www.naturalstandard.com).

References

Natural Standard developed the above evidence-based information based on a thorough systematic review of the available scientific articles. For comprehensive information about alternative and complementary therapies on the professional level, go to www.naturalstandard.com. Selected references are listed below.

1. Chung CH, Go P, Chang KH. PSK immunotherapy in cancer patients--a preliminary report. Zhonghua Min Guo Wei Sheng Wu Ji Mian Yi Xue Za Zhi 1987;20(3):210-216. View Abstract

2. Fisher M, Yang LX. Anticancer effects and mechanisms of polysaccharide-K (PSK): implications of cancer immunotherapy. Anticancer Res 2002;22(3):1737-1754. View Abstract

3. Hattori T, Nakajima T, Nakazato H, et al. Postoperative adjuvant immunochemotherapy with mitomycin C, tegafur, PSK and/or OK-432 for gastric cancer, with special reference to the change in stimulation index after gastrectomy. Jpn J Surg 1990;20(2):127-136. View Abstract

4. Ito K, Nakazato H, Koike A, et al. Long-term effect of 5-fluorouracil enhanced by intermittent administration of polysaccharide K after curative resection of colon cancer. A randomized controlled trial for 7-year follow-up. Int J Colorectal Dis 2004;19(2):157-164. View Abstract

5. Koda K, Miyazaki M, Sarashina H, et al. A randomized controlled trial of postoperative adjuvant immunochemotherapy for colorectal cancer with oral medicines. Int J Oncol 2003;23(1):165-172. View Abstract

6. Kono K, Kawaguchi Y, Mizukami Y, et al. Protein-bound polysaccharide K partially prevents apoptosis of circulating T cells induced by anti-cancer drug S-1 in patients with gastric cancer. Oncology 2008;74(3-4):143-149. View Abstract

7. Morimoto T, Ogawa M, Orita K, et al. Postoperative adjuvant randomised trial comparing chemoendocrine therapy, chemotherapy and immunotherapy for patients with stage II breast cancer: 5-year results from the Nishinihon Cooperative Study Group of Adjuvant Chemoendocrine Therapy for Breast Cancer (ACETBC) of Japan. Eur J Cancer 1996;32A(2):235-242. View Abstract

8. Nicandro JP, Tsourounis C, Frassetto L, et al. In vivo effect of I'm-Yunity on hepatic cytochrome P450 3A4. J Herb Pharmacother 2007;7(1):39-56. View Abstract

9. Ohwada S, Ogawa T, Makita F, et al. Beneficial effects of protein-bound polysaccharide K plus tegafur/uracil in patients with stage II or III colorectal cancer: analysis of immunological parameters. Oncol Rep 2006 Apr;15(4):861-8. View Abstract

10. Ohwada S, Ikeya T, Yokomori T, et al. Adjuvant immunochemotherapy with oral Tegafur/Uracil plus PSK in patients with stage II or III colorectal cancer: a randomised controlled study. Br J Cancer 3-8-2004;90(5):1003-1010. View Abstract

11. Sakamoto J, Nakazato H, Ichihashi H, et al. [The minimization method in a medium size clinical trial. Study of immunochemotherapy with PSK in gastric cancer]. Gan To Kagaku Ryoho 1988;15(6):1935-1942. View Abstract

12. Sakamoto J, Morita S, Oba K, et al. Efficacy of adjuvant immunochemotherapy with polysaccharide K for patients with curatively resected colorectal cancer: a meta-analysis of centrally randomized controlled clinical trials. Cancer Immunol Immunother 2006 Apr;55(4):404-11. View Abstract

13. Shibata M, Nezu T, Kanou H, et al. Immunomodulatory effects of low dose cis-Diaminedichloroplatinum (cisplatin) combined with UFT and PSK in patients with advanced colorectal cancer. Cancer Invest 2002;20(2):166-173. View Abstract

14. Sugimachi K, Maehara Y, Ogawa M, et al. Dose intensity of uracil and tegafur in postoperative chemotherapy for patients with poorly differentiated gastric cancer. Cancer Chemother Pharmacol 1997;40(3):233-238. View Abstract

15. Yamada T, Rino Y, Wada N, et al. [A case of long-term survival of 5 years after operation and chemotherapy for type 4 gastric cancer with peritoneal dissemination] Gan To Kagaku Ryoho 2008 Jan;35(1):117-9. View Abstract