[Bone marrow WT1 gene expression and clinical significance in chronic myelogenous leukemia]

To investigate the clinical significance of Wilms tumor gene (WT1) expression levels in the bone marrow (BM) of chronic myelogenous leukemia patients.

Real-time quantitative retroversion polymerase chain reaction (RQ-RT-PCR) method was established for detecting WT1 and GAPDH expression levels in the BM of 109 CML and 23 non-leukemic patients with Light Cycler. Normalized WT1 expression level (WT1(N)) was determined as a ratio between WT1 and GAPDH expression times 10(4).

The median expression levels of WT1(N) in 23 CML patients of accelerate phase (CML-AP) and 22 CML patients of blast crisis (CML-BC) were statistically higher than those of 64 CML patients of chronic phase (CML-CP) and 23 non-leukemic controls (103.71 and 129.44 vs 3.44 and 1.47). No statistic differences were found between the CML-CP group and control group, nor between the CML-AP group and CML-BC group. Furthermore, the WT1(N) levels were correlated to the BCR/ABL fusion gene expression levels. Dynamic change of WT1(N) levels in 7 CML patients before or after allogeneic bone marrow transplantation showed that WT1 expression levels could predict relapse of leukemia.

WT1 expression levels in CML patients in accelerate phase or blast crisis were strikingly higher than those in non-leukemic patients or CML patients in chronic phase, in whom WT1 expression was undetectable or showed low expression. WT1 gene could be an useful marker for detecting MRD and evaluating therapeutic efficacy in CML.