Trametes versicolor, has been assessed in phase I, II, and III randomized clinical trials in stomach, colorectal, esophageal, and breast cancer patients. Several clinical studies report significant immunologic and/or oncologic benefit of these fractions as adjunctive therapy in lung cancer patient's gastrointestinal cancers, and breast cancer.

Clinical trials using active fractions of Trametes (namely PSK and PSP) published in Japan and Korea suggest that T. versicolor polysaccharide-peptide constituents improve disease-free and overall survival in several different types of cancer, including stomach, esophagus, lung, colorectal, prostate, and breast adenocarcinomas. In Japan, PSK is a therapy prescribed to cancer patients routinely, both during and after radiation and chemotherapy, and it is a cancer therapy approved by the Japanese National Health Registry. However, no clinical trials have yet been carried out in the US.