OBJECTIVETo investigate the expression level of WT1 gene in bone marrow of patients with acute myeloid leukemia (AML) and its relationship with prognosis.

METHODSThe copy numbers of WT1 and internal reference gene in bone marrow samples from 75 newly diagnosed AML patients were detected by using real-time quantitative PCR. The gene WT1 expression level was determined by the ratio of the copy numbers of WT1 to reference gene. And the clinical characteristics, the complete remission (CR) rate after induction chemotherapy, 2-year overall survival (OS) rate and event-free survival (EFS) rate were calculated and analysed.

RESULTSThe expression level of WT1 did not significantly correlate with common clinical parameters such as age, sex, molecular abnormality, FAB classification and risk stratification. The CR rate in the high WT1 expression group before treatment was 65.4%, which was lower than that of 93.9% in the low expression group (χ2=8.25, P<0.01). The 2-year overall survival rate and event-free survival rate of the two groups were statistically significantly different (P<0.05), and the OS and EFS rates in high WT1 expression group were lower than those in low expression group. After the induction chamotheropy for about 1, 3 month and 6 months, the 2-year OS rate significantly increased in patients with decrease of WT1 gene expression level by one log or more (P<0.05).

CONCLUSIONThe expression level of WT1 gene in bone marrow may be an effective marker to evaluate therapy efficacy and prognosis for AML patients (non APL).