Expression of WT1 gene in acute leukemia and its significance

Abstract

Objective To explore the relationship between WT1 and prognosis of patients with acute myeloid leukemia (AML) or acute lymphoblastic leukemia (ALL), and to evaluate the possibility of WT1 as a potential marker for monitoring the minimal residual disease (MRD). Methods Bone marrow mononuclear cells from 58 patients with primary AML, 32 patients with primary ALL, 40 patients with AML-complete remission (CR), 28 patients with ALL-CR and 31 patients with trilineage hyperplasia (control group) were collected. Real-time fluorescent quantitative PCR method was used to detect the expression of WT1 in all patients. The expression threshold of WT1 in each group was established. WT1 copy number/ABL copy number ratio×100% denotes the relative expression level of WT1 gene. Results Median relative expression level of WT1 in the control patients was much lower than that in primary AML patients [0.026% (0-0.240%) vs. 20.880% (3.550%-48.500%), Z=-7.74, P 20.880%) was 60.7% (17/28), while the CR rate was 76.7% (23/30) in those with lower WT1 expression. WT1 expression was increased dramatically in recurrent AML patients. Relative expression level of WT1 was significantly higher in primary ALL patients [0.350% (0.021%-10.780%)] compared with that in the control group Z=-2.58, P<0.05. There was no significant difference in relative expression level of WT1 between ALL and ALL-CR patients [0.038% (0-2.800%), P=0.065]. Conclusion WT1 expression level in AML patients is relatively high, which could be used as an effective index of prognosis evaluation and MRD monitoring for AML patients, but not for ALL patients. Key words: Leukemia, acute; Gene, WT1; Polymerase chain reaction