Significance of quantification of MDR1 gene and CD56 antigen expression in acute myeloid leukemia patients
Objective To study the relationship between the MDR1 gene expressions and CD56 antigen expression in patients with de novo acute myeloid leukemia(AML) and to explore the role of this two factors in clinical drug resistance and their correlation. Methods A real-time quantitative RT-PCR method was established for detecting MDR1 expression levels and three-color flow cytometry analysis using CD34/ SSC gating was used to examined CD56 antigen expression in 79 de novo AML patients. Results CD56 an-tigen was recorded in 19 out of 79 cases (24.1%) and particularly in those with M5 cytotypes. Moreover, CD56 expression was significantly associated with unfavorable cytogenetic abnormalities (P<0.05), Patients with t(8:21)had a significantly higher incidence (57.1%, 4/7) of CD56 expression than those with favora-ble karyotype(P<0.05). CD56~+ AML patients had a higher incidence of splenohepatomegalia and lactate dehydrogenase level than CD56~- patients(P<0.05). The median expression levels of MDR1 was statistical-ly higher in CD56~+ AML patients than that in CD56 patients(P<0.001). Patients with both high levels of MDR1 and CD56~+ had a significantly lower CR(complete remission) rate than those with both low MDR1 level and CD56 (58.8% vs 89.2%, P<0.01). Conclusion There is a linear correlation between MDR1 gene expression and CD56 expression in AML. Quantification of the MDR1 gene expression together with CD56 antigen expression is more effective to the judgement of prognosis in AML. 
 
Key words: 
Acute myeloid leukemia;  Flow cytometry