Asparagine synthetase activity in paediatric acute leukaemias: AML-M5 subtype shows lowest activity

Lack of sufficient cellular activity of asparagine synthetase (AS) in blast cells compared with normal tissue is thought to be the basis of the antile ukaemic effect of L-asparaginase in acute lymphoblastic leukaemia (ALL), Al though L-asparaginase is routinely used in ALL, its role and Value in the t reatment of acute myelogenous leukaemia (AML) is still being discussed, To evaluate the pharmacological basis for L-asparaginase treatment, we establi shed pretreatment monitoring of the intracellular AS activity in blast cell s of patients with AML and ALL. There was no general difference in AS activ ity between ALL and AML samples, Significantly lower AS activity however, w as found in the B-lineage ALL subgroups as well as AML-M5.