[Clinical significance of multidrug resistance gene(mdr1) expression in patients with acute leukemia].

OBJECTIVE: To evaluate relationship between drug resistance of leukemia cells and prognosis. METHODS: The expression of multidrug resistance gene(mdr1) mRNA was measured in 85 patients with acute leukemia and in 20 normal controls by using reverse transcription polymerase chain reaction (RT-PCR). RESULTS: The mdr1 positive rate in untreated group was 44.7%. The CR rate differed significantly between mdr1+ (23.9%) and mdr1-(88.5%)(P < 0.005). The mdr1 positive rate of refractory-relapsed group was higher than that in CR group (P < 0.001). The mdr1 mRNA expression level of refractory-relapsed group was higher than that in CR group. A gradually increasing level of mdr1 mRNA expression in CR patients indicated early relapse. The mdr1 positive rate in normal contral and long-term surviver patients was very low. The mdr1 expression was correlated with French-American-Birtish Cooperative Group (FAB) classification. CONCLUSION: The mdr1 expression correlated with chemotherapeutic effect and prognosis. It is an unfavorable prognostic factor for patients with acute leukemia.