Plants, polysaccharides, and the treatment and prevention of neoplasia.

: Plants and Fungi have traditionally been the single largest source of lead compounds for the development of therapeutics by the pharmaceutical industry. Currently mushroom and plant polysaccharides brought to attention by Complementary and Alternative medicine, are undergoing scientific analysis and development to prevent and treat cancer, Two classes of saccharides are under investigation-beta glucan polysaccharides as biological response modifiers for the adjuvant treatment of cancer and "Oligosaccharin"-related oligosaccharides for the prevention of sun-induced skin cancer. Beta glucans already in human trials in the Far East will require mechanistic pharmacologic studies and definition of stucture function relationships before they are ready for clinical trials in the West. Other beta glucans that prime natural killer cells for antibody dependent cell-mediated cytotoxicity are approaching clinical trials. Oligosaccharides that downregulate production of immunosuppressive cytokines by ultraviolet radiation injured keratinocytes are promising agents for the prevention of environmental skin cancer.