Evaluation of the expression profile of MDR1 geneand assessment of its prognostic value in childhood ALL

Acute lymphoblastic leukemia (ALL) is the most common cancer among children. Multi drug resistance (MDR) is the major cause of treatment failure and relapse in ALL. ABC transporters mainly contribute to this disorder and MDR1 gene is the most popular member of this family. The aim of this study is to evaluate the gene expression profile of MDR1 at mRNA level and its prognostic value in ALL. Bone marrow and peripheral blood samples were obtained from 28 newly diagnosed ALL patients and 15 controls. MDR1 gene expression profile was evaluated by using real time PCR. The minimal residual disease (1-year MRD) was considered as the factor of response to therapy. Data were analyzed by using SPSS 20 and Graph Pad Prism 5 softwares. MDR1 gene expression level in patients with MRD+ was significantly higher than MRD- patients (2. 29 ± 1. 22 vs 0. 79 ± 0. 21) (mean ± SEM، p= 0. 049). Most of the patients with over expression of MDR1 gene were MRD+ (66. 6% vs 33. 3) (mean ± SEM، p= 0. 048). MDR1 gene expression profile is suggested to be an unfavorable prognostic factor in ALL. The evaluation of the mRNA expression profile of MDR1 in new case patients facilitates identification of the high risk patients and helps modifying the protocols applied for ALL treatment in order to improve the therapeutic outcome.