ANTHRACYCLINE RESISTANCE IN CHILDHOOD LEUKEMIA

Clinical resistance to anthracyclines, and the cardiotoxicity associat ed with the use of the conventional drugs daunorubicin (DNR) and doxor ubicin (DOX), initiated the search for new analogues and structurally related drugs. We use the cell culture drug resistance MTT assay to st udy the in vitro cytotoxicity of anthrracyclines in childhood leukemia . Here, we summarize our results regarding these agents. We also repor t that relapsed ALL samples were significantly more resistant to DNR, DOX, and mitoxantrone (MIT) than untreated ALL samples, while the anti leukemic activity of idarubicin (IDR) and especially of aclarubicin (A CR) was not significantly decreased in relapsed ALL.