A polysaccharide (GFP-A) from G. frondosa could significantly protect the thymus and spleen, inhibit the growth of S180 tumor cells by inducing cell cycle arrest in the G1 phase and apoptosis, enhance the killing activity of NK cells, the phagocytic ability of macrophages, and the proliferation activity of splenic lymphocytes, and promote the secretion of cytokines such as TNF-α, IL-2, and IFN-γ to enhance immune function in vivo [35]. The gene discussed is IL2; the disease is neoplasm.