The growth-inhibitory action of heparin on the Ehrlich ascites tumor in mice.

Heparin acts as a mitotic inhibitor on the Ehrlich ascites tumor in vivo , as shown by a highly significant decrease in the mitotic index following the single but not the repeated injections. This reduction in the mitotic index is reflected by tumor regression to the extent of a 40–50 per cent decrease in tumor volume. The experimental conditions employed produced no effect on the survival time of the treated animals. It is suggested that heparin exerts its effects directly on the tumor cells rather than indirectly following hemorrhage.