Figure 7. Timing of ATRA treatment and acquisition of BCR-ABL mutation.

(A) KCL-22 cells were treated with DMSO (CTL) and 0.1, 1, 5 or 10 µM ATRA for 24 h. Cells were harvested and washed thoroughly with phosphate-buffered saline, and then replated with 2.5 µM IM without ATRA for relapse assay. (B) After initiation of KCL-22 cell treatment with 2.5 µM IM for 0, 1, 3, 5 and 7 days, 1 µM ATRA was added. Cell count was performed from the initiation of IM treatment.