Different stages of tumor development are unequally affected by pretreatment of tumor cells with a polysaccharide.

Pretreatment with the polysaccharide levan of Lewis lung carcinoma and AKR lymphoma cells affected unequally different stages of tumor development. While levan pretreatment sharply reduced the evolution of tumors from subcutaneously inoculated cells, no such inhibition was observed with pretreated cells inoculated intravenously. Since levan is known to affect the cell membrane, it is concluded that different cell membrane properties may be involved in the various stages of tumor progression.