Anti-tumor effect of 4-MU in a peritonitis carcinomatosa model. (A) Rats in the control group did not survive after day 13. The survival times were significantly prolonged in the 4-MU-treated group compared with the control group (P < 0.05). (B) There was a significant difference in body weight gain between the 2 groups due to increased malignant ascites. *P < 0.05 (C) Differences in peritoneal tumors between the 2 groups. Rats in the control group developed large peritoneal tumors, whereas tumor sizes were smaller in rats in the 4-MU-treated group. The arrows indicate peritoneal tumors.