Medicinal mushrooms are among the most commonly prescribed anticancer natural products with data from controlled clinical trials suggesting possible benefit in cancer treatment.42 Maitake mushroom (Grifola frondosa) is among those used. Medicinal mushrooms contain a class of polysaccharides known as beta-glucans that promote antitumor immunity related to antibody–Fc interactions by activating complement receptors. Mouse models have demonstrated that beta-glucans act synergistically with therapeutic antibodies such as trastuzumab or rituximab.42
Human data are limited, and at this time there is insufficient evidence to recommend for or against the use of oral maitake for any indication; however, they are commonly ingested as a food and appear safe for general consumption.
Edible (Medicinal) Mushrooms
Medicinal mushrooms that have an antiinflammatory and immune-enhancing effect include maitake (Grifola frondosa), shiitake (Lentinus edodes), reishi (Ganoderma lucidum), and turkey tail (Trametes versicolor).73 Mushrooms also have a number of other properties, including antifungal, antibacterial, antiviral, and tumor attenuating. Each mushroom has different characteristics. Maitake mushrooms in particular have high antitumor and antiinflammatory activity.74 In one phase I/II trial of maitake extract, a statistically significant association was found with positive immune response. There was no dose-limiting toxicity.75 In a review of T. versicolor research in Japan and China, Standish et al.76 discussed data suggesting that this mushroom improves disease-free intervals and overall survival in breast cancer patients by immune modulation. More research is warranted.