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

The effectiveness of heparin as a mitotic inhib itor in vitro has been shown on marine eggs (8), on tumor tissue (6, 17), and on tissue culture (2, 5). The use of an ascites tumor in these experiments has made possible the demonstration of the mitotic inhibitory activity of heparin on tumors in vivo. Balazs and Holmgren (1) reported a growth-in hibitory activity of heparin on tumor tissue by showing an increase in survival time of animals when heparin treatment was begun immediately following tumor transfer. Negative effects on tu mor growth were obtained by Shear (15) and Kreisler (11). These latter results may be at tributed to the technics employed, which involved in one case toxic doses, and, in another, intra venous injection of the heparin. The results reported in the present work clearly show that heparin is a mitotic inhibitor in the ascites tumor in vivo and consequently checks tumor growth. There is further indication that such activity is not of necessity followed by an increase in survival time.