We found a concomitant increase in mdr1 and mrp gene expression combined with a decreased expression of topoisomerase II alpha in the course of the second relapse of an acute lymphoblastic leukemia (ALL).
Analysis of paired samples, the first obtained at diagnosis and the second at relapse, from 13 acute myelogenous leukemia (AML) and four acute lymphocytic leukemia (ALL) patients showed that MRP expression was increased at the time of relapse in greater than 80% of patients.
P-glycoprotein (P-gp), lung resistance-related protein (LRP) and multidrug resistance-associated protein (MRP) expression, and blast cell intracellular daunorubicin accumulation (IDA) were evaluated in 95 previously untreated cases of adult acute lymphoblastic leukaemia (ALL) using flow cytometry.
MRP gene expression was found to be higher in patients with relapsed de novo AML compared to those at presentation but prior therapy did not affect MRP gene expression in ALL.
Bone marrow aspirates from 30 children with a diagnosis of acute lymphoblastic leukemia were assessed for the expression of messenger RNA for the MDR-1, MRP and LRP genes by semi-quantitative RT-PCR.