Opposite effects on tumor growth depending on dose of an immunomodulatory polysaccharide with or without cyclophosphamide.

Opposite effects on the growth of the F10 variant of B16 melanoma--inhibitory and stimulatory--were found with varying doses of the polysaccharide levan. Low (0.1 and 1 mg) daily doses inhibited, while high (5 and 10 mg) doses enhanced tumor growth. In combined cyclophosphamide-levan treatment, these opposite effects were more pronounced.