BCRP mRNA expression v. clinical outcome in 40 adult AML patients.

Efflux pumps are considered being mechanisms behind drug resistance in acute myeloid leukaemia (AML). A recently described efflux pump, breast cancer resistance protein (BCRP), can be expressed in AML, but its clinical importance is uncertain. In this study BCRP mRNA expression was determined in samples from 40 AML patients by real-time RT-PCR. The expression varied from negative to 76 times that of control cells. There was no difference in BCRP mRNA expression between patients responding to induction treatment and non-responders. However, in the group of responders, the 14 patients with the highest expression had significantly shorter overall survival (mean 38 months, SEM 15 months) than the 14 patients with the lowest (74 months, SEM 16 months) (P = 0.047). This suggests a possible role of BCRP in drug resistance in AML.