[Expression of multidrug resistance 1 and correlation with clinical drug resistance in acute leukemia]

Expression of multidrug resistance (mdr 1) gene, which encodes a transmembrane efflux pump referred to P-glycoprotein, leads to the decreased intracellular accumulation of various lipophilic drugs, such as vinca alkaloids, anthracyclines and epipodophyllotoxins. As these drugs are commonly used in chemotherapy for acute leukemia, it is of importance to determine whether mdr 1/P-glycoprotein expression is associated with clinical resistance. In several reports, some leukemia cells from untreated patients have expression of mdr 1/P-glycoprotein. We quantitatively detected low levels of mdr 1 expression in all cases of untreated acute leukemia and normal hematopoietic cells, using the reverse transcriptase-polymerase chain reaction. Carefully designed clinical trials including mdr 1 reversing agents may have significant consequences for the treatment of acute leukemia.