MD Anderson Cancer center has some significant findings about Coriolus versicolor PSP & PSK. We have collated the appropriate material below and in subsequent post. (See www.mdanderson.org)

Mushrooms have been used for at least 5000 years for nutritional and medicinal purposes. Anti-viral and anti-cancer effects have been demonstrated in more than 50 species through animal and in vitro studies. Six components of these mushrooms have been investigated for their activity in human cancers: the lentinan component of shiitake, schizophyllan, active hexose correlated compound (AHCC), maitake D-fraction and two components of Coriolus versicolor.

According to the review by Kidd, lentinan and schizophyllan have limited oral bioavailability, and the AHCC and maitake D-fractions are still in the early stages of investigation, but the two Coriolus versicolor components have been extensively investigated and show promise.
Coriolus versicolor was first recorded during the Ming Dynasty of China, and subsequently in a 1965 Japanese report of a patient with stomach cancer who benefited from drinking a tea, Saru-no-koshikake, that contained this mushroom. Subsequent laboratory and animal research identified the source of the tea’s anti-tumor effects to be two polysaccharides*.
In 1989, two investigators at the U. S. National Cancer Institute (Jong and Donovick7) published a review of antitumor and antiviral substances from fungi including Coriolus versicolor. This review noted seven studies and two U. S. patents issued for polysaccharides extracted from Coriolus versicolor. One extract was a polysaccharide-protein (proteoglycan) known as polysaccharide Kurcha (PSK or Krestin), and it had been found to be effective in the treatment of Ehrlich carcinoma and sarcoma 180 tumors in mice. Furthermore, PSK had not exhibited any of the cytotoxicity or other side effects commonly seen with conventional anticancer treatment.
Subsequent laboratory and animal studies have further defined the antitumor, antimicrobial, antiviral and immune enhancing properties in both PSK and another protein-bound polysaccharide known as polysaccharide-protein complex (PSPC or PSP). Both substances are extracted by hot water from the mushroom’s cultured mycelium (thread-like extensions)