[Proliferation kinetics of Ehrlich ascites tumors during cisplatin administration]

In order to study the relationship between numerical growth and DNA-frequency distribution of tumor cells model experiments were made on the Ehrlich ascites tumor of mice after a single doses of the cytostatic cis-Platin. In 84 mice the tumor growth was measured by cell counting and the DNA-histogram by flow-cytometry. With exception of the controls 4, 8, 16 mg cis-Pt/kg were applied i.p. at the 5th day of tumor growth. An inhibition or a retardation of tumor growth is always observed. The 4 mg doses leads to a G2-blockade resulting in an increase of the G2-peak in the DNA-histogram after 2 days (7th day of growth). After 7 days of tumor growth) the effect has been mainly subsided. The effect of 16 mg/kg is a blockade of G2- and S-phase as well, connected with a complete inhibition of tumor growth. Therefore after two days (7th day of growth) this DNA-histogram is very similar to that of the control. Later on a recovery of DNA-synthesis occurs while the G2-blockade is still existing. Therefore the G2-peak is very marked 7 days after application (12th day of growth). All doses result in a disturbance of higher ploid cycles with an increase of hyper-8c-nuclei.