In vivo and in vitro detection of induced resistance to daunorubicin in murine leukemia L 1210.

By treatment of the mouse leukemia L 1210 with daunorubicin (2 mg/kg per week) a tumour cell line was developed which was resistant to this cytostatic agent. The sensitive and resistant tumour cell line could be distinguished using an in vitro short-term test. Cross resistance could also be reliably detected by this method. In all cases, a good correlation was observed between the results of in vitro short-term tests and animal experiments.