Acute leukemia a quite homogenous disease failed to break through the sound barriere of when untreated reveals a substantial hetero- unsatisfactory cure rates even in special sub- geneity in its response to therapy. While cure groups. While new protocols including more is achieved in a certain proportion of pa- effective supportive care show some increase tients other cases prove to be highly resis- in the initial response rates and certain im- tant. The curability is superior in acute provements in the long-term results, no ben- lymphoblastic (ALL) than in acute myeloid eficial effect on the relapse rate during the (AML) leukemia and - within both type- first 1 Y2 years emerged from any of these higher in children as compared to adults. regimens. Thus, high chances for cure are The two age groups and cell types can be presently restricted to children with ALL further subdivided into prognostic groups and to lesser proportions children with by special diagnostic features. Thus, in AML and adults with ALL and AML.