Pgp activity was higher in CD34+ leukemia than in CD34- leukemia (2.26 +/- 1.50 v 1.46 +/- 1.21, respectively; P = .003), and MRP activity was higher in CD34- leukemia than in CD34+ leukemia (1.77 +/- 0.40 v 1.4 +/- 0.29, respectively; P = .004).
Sequential emergence of MRP- and MDR1-gene over-expression as well as MDR1-gene translocation in homoharringtonine-selected K562 human leukemia cell lines.
These findings provide important insight into the biology of inversion 16 leukaemia and suggest that MRP deletion, as detected by molecular analysis, may have a key role in determining outcome in patients with inversion 16 AML.