A 2017 Polish study has demonstrated antitumor and immune-modulating effects of polysaccharide compounds and extracts from chaga. In vivo experiments on animals implanted with tumor cells of different types demonstrated that with chaga, the immune system was activated, and led to prolonged survival and decreased tumor sizes.
S Justyna, S Marcin, I Ewa. Antitumor and immunomodulatory activity of Inonotus obliquus. Herba Polonica, 63(2), 48-58. (2017)