We conclude that measurement of Rh123 efflux and immunocytochemical staining of cytospin preparations with JSB1 allows the accurate monitoring of P-170 expression in acute leukemia.
No differences between expression of P-gp and BCRP and genes in primary and relapsed acute leukemia (AL) cells as well as in de novo and treated CLL samples were established.
Thus, P-glycoprotein expression and mdr1 gene amplification occurred infrequently not only in leukemia cells at the initial presentation but also in those at the relapsed cases and may not be a major cause of refractoriness to antileukemia drugs in adult acute leukemia.
A semi-quantitative reverse transcription polymerase chain reaction (RT-PCR) was used to investigate and compare transcription levels of the human multidrug resistance gene (MDR1) and the recently described multidrug resistance-associated protein (MRP) in 105 samples from patients with acute leukaemia at presentation and relapse.
We therefore investigated, whether P-gp expression levels or functional P-gp activity better predict response to induction chemotherapy, relapse rate and overall survival in acute leukemia.
It may be speculated that precytotoxic agents induced mdr1 and mdr3 P-gp expression in acute leukemia; however, in chronic leukemia, both P-gps were expressed independently of exposure to precytotoxic agents.
Investigations of mdr1 regulation in normal hematopoietic elements has shown a pattern which corresponds to its regulation in acute leukemia, explaining the linkage of mdr1 to specific cellular phenotypes.
In this article, we review the different methods for determining MDR and, in particular, methods for determining P-gp/MDR1, with special reference to their potential importance for therapeutic strategies in human acute leukemia.
Prognostic significance of multidrug resistance gene 1 (MDR1), multidrug resistance-related protein (MRP) and lung resistance protein (LRP) mRNA expression in acute leukemia.
These results showed the potential clinical relevance of MDR1, MRP1 and BCL-2 in adult patients with acute leukemia in the context of induction chemotherapy.
The present data indicate that abcb1 gene overexpression may be associated with a poor prognosis in adults with AL and that ABCB1 and abcc1 expression correlates with different prognostic factors in pediatric patients with AL.
Both the expression of the multidrug transporter, P-glycoprotein (Pgp), and abnormalities of the long arm of chromosome 7 have been shown to be adverse prognostic indicators in acute leukemias.