Polysaccharide-K (PSK) increases p21(WAF/Cip1) and promotes apoptosis in pancreatic cancer cells.

Polysaccharide-K (PSK, Krestin(®)) is a natural remedy and one of the most commonly used medicinal mushroom extracts. It has been used as oral adjuvant treatment in cancer therapy in Japan and other Asian countries for more than 40 years. PSK is thought to be an immune modulator, however, its antitumor actions remain undefined. The aim of the present study was to investigate underlying mechanisms by which PSK exerts its antitumor effects on malignant epithelial cells