Maitake and Shiitake Mushrooms
Chang R. "Functional Properties of edible mushrooms." Nutr Rev 1996. 54(11 Pt 2): S91-3. Kim HS, Kacew S, Lee BM. "In vitro chemopreventive effects of plant polysaccharides (Aloe barbadensis miller, Lentinus edodes, Ganoderma lucidum and Coriolus versicolor)." Carcinogenesis 1999. 20(8): 1637-40. 

Kurashige S, Akuzawa Y, Endo F. "Effects of Lentinus edodes, Grifola frondosa and Pleurotus ostreatus administration on cancer outbreak, and activities of macrophages and lymphocytes in mice treated with a carcinogen, N-butyl-N-butanolnitrosoamine." Immunopharmacol-Immunotoxicol 1997. 19(2): 175-83. 

Kurashige S, Akuzawa Y, Endo F. "Effects of Lentinus edodes, Grifola frondosa and Pleurotus ostreatus administration on cancer outbreak, and activities of macrophages and lymphocytes in mice treated with a carcinogen, N-butyl-N-butanolnitrosoamine." Immunopharmacol Immunotoxicol 1997. 19(2): 175-83. 

Ooi VE, Liu F. "Immunomodulation and anti-cancer activity of polysaccharide-protein complexes. Curr Med Chem 2000. 7(7): 715-29.