Sarcoma 180 weight, DNA, and protein increase, depending on ARA-C schedule.

The authors studied the effects of cytosine arabinoside (ara C) administration to mice with the solid form of Sarcoma 180 for a 30 day period. The drug was administered by oral or intraperitoneal routes in single daily doses of 5, 10 and 20 mg/kg. This treatment resulted in an increase in tumor weight and a decrease in average survival rate inversely proportional to the dose administered. Likewise, DNA and protein content of the Sarcoma 180 mass increased. While red blood cells showed a linear regression independently of the administration route, leukocytes decreased after oral treatment only. The possible mechanism that regulates paradoxical growth of Sarcoma 180 induced by spaced doses of ara C is discussed.