A very interesting read!!! Part 1 of 2


PSP, a polysaccharopeptide obtained from cultivated mycelia of the mushroom Coriolus versicolor, is a biological response modifier capable of howing diverse biological activities. It is a chemically homogenous substance possessing a molecular weight of approximately 100 kilodaltons. PSP is composed of 90% polysaccharides and 10% peptides. In addition to glucose, its polysaccharide constituents consist of five other sugars including arabinose, galactose, mannose, rhannose and xylose. The polypeptide constituents contain more than twenty different amino acids, notably aspartic and glutamic acids. PSP exhibits immunomodulatory and anti-tumour activities with low cytotoxicity. It has been used in Asia, particularly in China, as an adjuvant in the clinical treatment of cancer to boost the immunological
status of patients undergoing chemotherapy and/or radiotherapy. In addition, PSP exhibits analgesic, anti-viral and hepato-protective effects. Cancer is the result of changes in key regulatory genes which control cell proliferation, differentiation and survival. Cancer development is a multi step complex process in which normal cells gradually progress to malignancy. Both the activation of the oncogenes and the inactivity of the tumour suppresser genes are critical steps in tumour initiation and progression. The failure of cancer cells to undergo programmed cell death, known as apoptosis, is a critical factor in the development of tumours. The immune response mounted by the body is of major importance in preventing this process happening, or if it has happened, moving it towards the direction of normal apoptosis. (Rudin C M & Thompson C B 1997).

Dr. Kenyon is the founder of the Dove Clinic for Integrated Medicine, London and Twyford (near Winchester) / ( ) The activity of the immune system is firstly non-specific, mediated by natural killer cells, and secondly tumour antigen specific by mounting a cell mediated

2. Immune response known as a thymic helper cell one (TH1) response. Most commonly cancer patients mount a marked thymic helper cell two (humoral immunity), a so-called TH2 response which involves production of large quantities of antibodies (Kenyon 2001 Gotos et al 1999). TH1 cells produce one set of cytokines whilst another set of cells, the TH2 cells, produce another set of cytokines. The cytokines produced by the two cell groups both influence the anti-cancer defence mechanism in a different way. Amongst the cytokines produced by the TH1 cells there is Tumour Necrosis Factor Beta which is known for it’s ability to destroy cancer cells. However, if the TH1 response is suppressed, Tumour Necrosis Factor Beta can be produced by natural killer cells. An effective anti-tumour response is a cell mediated TH1 immune response. If the TH2 humoral response is
excessively activated then a set of cytokines, amongst which is Interleukin 5, will be produced and these can negatively affect the anti-cancer defence mechanism either directly, or indirectly. A recent study has shown that medium and high cytotoxic activity of peripheral blood lymphocytes (mediated by TH1 lymphocytes and also natural killer cells in a non-specific way), is associated with reduced cancer risk. Whereas low activity is associated with increased cancer risk, suggesting a role for natural immunological host defence mechanisms against cancer (Kazue Imai et al 2000). Telomerase is a ribonucleo protein polymerase and is an enzyme whose function is to maintain the essential genetic element of telomeres, the eukaryotic ends of chromosomes. Telomerase activity becomes suppressed in the ageing process, but activation of telomerase is regarded as essential to
most cancers. This means that there is a specific association of human telomerase activity with cancer and usually it is high in cancer patients. There is clinical evidence to show that patients’ who have tumours that do not display telomerase activity are likely to eliminate the cancer, quite often spontaneously. It is considered that the repression of telomerase activity
could be one of the mechanisms for cancer regression (Shay J W & Wright W E 1998). Several medicinal mushrooms are available for medical use at the present time. More than 50 mushroom species exhibit anti-cancer activity in-vitro, or in animal models, and of these, 6 have been investigated in human cancers. All are non-toxic and very well tolerated. Two proteoglycans from Corioulus versicolor-PSK (Polysachharide/K) and PSP (Polysachharide-peptide) – have demonstrated the most promise. Both have been subject to Phase II and Phase III trials in China, and PSP significantly extended 5 years survival in oesophageal cancer. PSP also significantly improved quality of life, provided substantial pain relief and enhanced immune status in 70-97% of patients with cancers of the stomach, oesophagus, lung, ovary and cervix. PSK and PSP boosted immune cell production, ameliorated chemotherapy symptoms,
and enhanced tumour infiltration by dendritic and cytotoxic T-cells. They have extremely high tolerability, proven benefits to survival and quality of life, and their compatibility to chemotherapy and radiation therapy makes them well suited for cancer management regimens (Kidd, P.M. “The use of mushroom glucans and proteoglycans in cancer treatment”. P.M. Altern MedRed 2000: 5 (1): 4-27).