ATSO, an antitumor polysaccharide from Coriolus versicolor, was found to strongly suppress the growth of a solid-type sarcoma-180 in mice. The additive effect of ATSO and anticancer chemotherapeutics on antitumor activity and immune response was examined in tumor-bearing and normal mice. The delayed cutaneous hypersensitivity (DCH) of mice was depressed after implantation of tumor and treatment with antitumor chemotherapeutic drugs. ATSO inhibited the depression of DCH by intraperitoneal or oral administration, but ATSO did not increase DCH of normal mice. The combination treatment of a low dose of ATSO and drugs was found to promote tumor regression significantly in mice.
