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.
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.
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.
Multidrug resistance (Mdr1) gene expression in peripheral blasts from patients with acute leukemia only rarely increases during disease progression after combination chemotherapy.
These results suggest that MDR1 gene expression can be used as a prognostic factor and may be helpful in determining chemotherapeutic protocol for patients with acute leukemia.
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.
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.
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.
Prognostic significance of multidrug resistance gene 1 (MDR1), multidrug resistance-related protein (MRP) and lung resistance protein (LRP) mRNA expression in acute leukemia.