Antitumor effect of polysaccharide lentinan on MH-134 ascites hepatoma in C3H/He mice

Lentinan inhibited the proliferation of MH-134 ascites hepatoma transplanted subcutaneously. The best result occurred when 1 mg-2 mg/kg of lentinan was administered for 10 consecutive days from the eighth day after tumor transplantation. Tumor proliferation was 33% inhibited as measured by the average tumor diameter. The average survival (days) when chemotherapy with mitomycin-C (MMC), 5-FU and Ara-C in combination with lentinan, was administered concurrently in the second week of the tumor transplantation was 29.2 days as compared to 20.5 days in the untreated group, 25.1 days in the group given lentinan alone, and 22.0 days in the group receiving chemotherapy alone. When lentinan was administered in combination with bacterial lipopolysaccharide (LPS), the group given lentinan for 5 consecutive days from the third day after tumor transplantation and 30 micrograms LPS i.p. on the thirteenth day, had 70% inhibition of tumor as measured by the average tumor weight. The antitumor activity of lentinan was studied by following changes in macrophage migration inhibition activity (MI). In the untreated group, MI activity disappeared on the 14th day after tumor transplantation. In the group treated with lentinan, spleen cells had positive activity suggesting a restorative action of lentinan on the immune suppression accompanying tumor growth.