PCR analysis at primary diagnosis and remission. Standard diagnostic PCR was performed on DNA derived from bone-marrow aspirates at primary diagnosis and remission. The PCR assay used allows a sensitivity above 1:100 (as tested using MV4;11 cells as a positive control in comparison to healthy donor PBMC). FLT3-ITD mutations were detectable in samples of both patients at diagnosis (lane 2 - patient 2 and lane 4 - patient 1). Complete molecular remission could be confirmed in both remission samples (lane 3 - patient 2 and lane 5 - patient 1). MV4-11 cells served as positive control (lane 7) and healthy donors or water as negative controls (lane 6 and 8).