Presence of BCRP only in subpopulations and discordance among BCRP measurements suggest complex biology of BCRP in AML and incomplete modeling by cell lines.
The relative expression of the drug-efflux pumps P-gp, MRP, LRP, and BCRP was evaluated by mean fluorescence index (MFI) and the Kolmogorov-Smirnov analysis (D values) in five leukemic subpopulations: CD34+CD38-CD123+ (LSCs), CD34+CD38+CD123-, CD34+CD38+CD123+, CD34+CD38+CD123-, and CD34- mature cells in 26 bone marrow samples of CD34+ AML cases.
At diagnosis BCRP activity was undetectable in AML blasts from 23/26 cases, while Pgp activity was present in 36/45 and MRP activity in 26/44 of the cases.
Recently, the breast cancer-resistant protein (BCRP), the equivalent of mitoxantrone-resistant protein (MXR) or placental ABC transporter (ABCP), was described in AML.