Medicinal Mushrooms and Cancer: Research Overview
Healing mushrooms were traditionally used for many different conditions. However, early researchers were most interested in their effects against tumors, and especially cancer (malignant tumors).
Medicinal mushroom research in the East
Modern research of medicinal mushrooms started in Japan when Dr. Kisaku Mori established the Institute of Mushroom Research in Tokyo in 1936. The primary goal of the Institute was to gather and critically analyze the methods and experiences of traditional use.
Most research on anticancer effects of mushrooms was done in Japan, at the Research Institute of the National Cancer Centre in Tokyo. In 1969, prof. Tetsuro Ikekawa verified the healing effects of 7 edible mushroom extracts on mice with sarcoma 180. In the same year, prof. Goro Chihara has published a short article in Nature on the antitumor effects of lentinan (compound from shiitake), and in 1970 in Cancer on its isolation, chemical structure, and anticancer activity.
In 1974, Hamuro and Chihara confirmed and expanded these findings in a joint study with the Japanese food company Ajinomoto. About the same time, Chihara has also published research on the preventive and therapeutic effects of lentinan on cancer metastasis.
The most important results of this research follow below:
|Medicinal mushroom||Cancer regression rate||Complete regression|
|Ganoderma lucidum (reishi)||98.5%||4/5|
|Lentinus edodes (shiitake)||80.7%||6/10|
|Trametes versicolor (turkey tail)||77.5%||4/8|
Certain extract isolates caused 100% cancer regression rate.
Further research by Mori, Ikekawa, Hamuro, Chihara, Maeda, Taguchi, Nanba, Aoki, Ohno and many others, has proven that medicinal mushroom can cause significant cancer prevention and cancer regression (in various types of cancer), including complete regression if used on time.
Consequently, 3 official mushroom drugs have been registered for use in Japan: PSK (Krestin; 1977 from Trametes versicolor), lentinan (Lentinan; 1985 from Lentinus edodes = shiitake) and SPG (Sonifilan; 1986 from Schizophyllum commune). All of them are still in use in Japan.
Chinese scientists (Xiao-Yu Li, Jia-Fang Wang, Q. Y. Yang and many others) have been just as active, and reached similar results.
In China, Prof. Q. Y. Yang isolated polysaccharide-peptide, or PSP, from Trametes versicolor. PSP is the first official drug made from medicinal mushrooms against cancer in China: it was registered in 1983 and is still in use. Chemically, PSP is very similar to PSK (Krestin), an official anticancer drug in Japan since 1977. PSK (Krestin) is still used in Japan, Australia and other countries.
Today, a majority of research comes from China.
Cancer Research in the West
The research of medicinal mushrooms and cancer in the West started surprisingly early. In 1958, E. H. Lucas (University of Michigan) confirmed that calvacin – the active ingredient of Calvatia gigantea (giant puffball) – fights cancer. The study would not be possible without direct collaboration between Lucas and K. Mori, one of the Japanese pioneers in the field.
L. Hartwell composed the first extensive overview of traditional folk medications used against cancer in 1967. Beside plants it lists mushrooms – edible, inedible and even some poisonous ones.
Ever since 1999 when professors Solomon Wasser, Shu-Ting Chang and Takashi Mizuno founded the International Journal of Medicinal Mushrooms, and in 2001 started biennial International Medicinal Mushroom Conferences, the Western scientists’ contribution (to the field) greatly increased.
However, the majority of medicinal mushroom research is still done in the Far East. Crucially, none of more than 400 human clinical trials have been carried out in the West, mostly due to overly restrictive health authorities and higher costs.
EDIT: In 2012, a small-scale phase 1 clinical trial was completed in the USA by Torkelson et al., in a joint effort from the University of Minnesota and Bastyr University. The study examined Trametes versicolor (= Coriolus versicolor, Turkey Tail Mushroom) in 9 breast cancer patients who had undergone surgery and chemotherapy and were starting radiation therapy. One of the goals was assessing safety: the patients received up to 9 grams/day for 9 weeks; the mushroom was well tolerated and the upper limit was not reached. The study also suggests that Trametes versicolor is a safe immunotherapy for breast cancer patients that may correct radiotherapy-related immune defects, increasing lymphocyte count and NK cell antitumor activity.