Resistance testing and mechanisms of resistance in childhood leukemia. Studies from Amsterdam.

The prognosis of children with leukemia has improved dramatically due to the development of effective combination chemotherapy. Nevertheless, about 25% of children with acute lymphobalstic leukemia (ALL) and 50% of children with acute myeloid leukemia (AML) die of resistant or relapsed disease. On the other hand, patients who are curable with relatively mild chemotherapy as used in the seventies, will nowadays be overtreated and suffer from unnecessary side-effects. This is due to the fact that therapy has been intensified for all patients in (successful) attempts to cure an increasing number of children. Therefore, it is of the highest importance to identify children with highly sensitive leukemia that can be cured with minimal therapy and children who need specifically intensified therapy. Our research program focusses on the relation between molecular biological characteristics, drug resistance and prognosis in pediatric oncology. Here, results from some recent and currently ongoing studies in leukemia will be described.