Lentinan is a beta glucan found in shiitake mushrooms (Lentinus edodes).

Lentinan stimulates increased production and activity of natural killer cells and macrophages, which destroy tumor cells.

References

Mizuno T. Shiitake. Lentinus edodes: functional properties for medicinal and food purposes. Food Rev Int 1995;11:111–28. Borchers AT, Stern JS, Hackman RM, Keen CL, Gershwin ME. Mushrooms, tumors, and immunity. Proc Soc Exp Biol Med. 1999; 221:281-293. Chang R. Functional properties of edible mushrooms. Nutr Rev. 1996; 54:S91-S93.Kidd P. The use of mushroom glucans and proteoglycans in cancer treatment. Altern Med Rev. 2000; 5:4-27.