The Relation Between WT1 Gene And The DNA Methylation Pattern Of That Promoter In Leukemia

Objective : To investigate the role of WT1 gene in dectecting the treament result and the mininal residual disease(MRD) of acute leukemia (AL).To explore the DNA methylation patterns of WT1 gene promoter region within acute leukemia, the correlation between that and WT1 gene expression and clinical significance.Methods:Real-Time Fluorescence quantitative PCR was used to amplify B₂-MG and WT1 gene from cultivated K562 cells. Standard curves were constructed by performing Real-Time PCR on a standard template after 10-fold serial dilutions of cellular cDNA. Then detected the WT1 mRNA levels of these samples from 64 leukemia patients and 56 controls. Surveyed were the DNA methylation patterns of WT1 gene in the same samples by Methylaion specfic polymerase chain reaction, the connection between the level of WT1 gene expression and the DNA methylation patterns of its promoter regeion.Results : All the samples were divided to 3 groups. The first group of 40 patients with AL(relapsed , untreated and not remitted), accelated phase or blast crisis of chronic granulocytic leukemia show higher WT1 gene expression level, ranging from 22．54-168．90copies /100ngRNA . The second group of 24 patients(remitted and chronic phase of chronic myeloid leukemia)show WT1 expressions from 0-4．90copise/100ngRNA .The third group of 56 healthy people and other non-patients show a much lower WT1 level , from 0-3．20copise/100ngRNA. The WT1 expression level in group 1 is 10 times higher than those in group 2 and group 3 , while there is no sharp difference in group 2 and group 3 .There was negative correlation between DNA methylation status in WT1 promoter region and the level of WT1 mRNA in bone marrowThe DNA demethylation in WT1 promoter region demonstrated higher WT1 expression in acute leukemia patients (relapsed , untreated and not remitted), in the accelated phase or blast crisis of chronic granulocytic leukemia patients.However, The DNA hypermethylation statuses in WT1 promoter region demonstrated a lower WT1 expression in chronic phase of CML, remitted patient,nomal hunman and other patients whose diseases were non-leukemia.Conclusion : The method of FQ-PCR is objective and accurate. The WT1 levels remain different with different disease phases. The gene expression increase in acute leukemia patients , can be used to detect the minial residual diseade , and correlate with the treatment results and prognosis of AL and CML.The DNA methylation in WT1 gene promoter may be one of the menchanism to supress its expression. To make DNA hypermethlation in WT1 gene promoter region will inhibit the expression of WT1 mRNA and become one method to cure and prevent leukemia .