PSK, a proteoglycan from Coriolus versicolor, is an immunomodulator which has been used in conjunction with cancer adjuvant immunotherapy in Japan for decades.
Randomised controlled human clinical trials have documented that PSK has anticancer activity by boosting cellular immune function in the host to defend against tumour progression.
PSK significantly extended disease-free survival at 5 years or more in cancer of the colon-rectum, stomach, oesophagus, nasopharynx, non-small cell type lung cancer, and in HLA-B40 positive breast cancer subjects. Meta-analysis of randomised controlled trials has confirmed the efficacy of PSK in adjuvant immunotherapy for patients with curatively resected colorectal cancer.
PSK significantly enhanced the quality of life and boosted the production of immune effector cells and cytokines to improve immune status in patients with cancer. PSK is well-tolerated and compatible as an adjuvant immunotherapy with surgery, chemotherapy and/or radiation therapy.