Value of Wilms tumor 1 gene combined with multiparameter flow cytometry for minimal residual disease in evaluating prognosis of children with acute myeloid leukemia

Objective To analyze the value of Wilms tumor 1 (WT1) gene combined with multiparameter flow cytometry for minimal residual disease (FCM-MRD) in evaluating prognosis of children with acute myeloid leukemia (AML).

Methods The clinical data and general information of 76 children with AML were retrospectively analyzed. Before treatment, WT1 gene expression was detected by real-time fluorescence quantitative polymerase chain reaction (qRT-PCR) in all the children, and MRD was detected by FCM. All the children were followed up for a year, and they were divided into good prognosis group (n=40) and poor prognosis group (n=36) according to prognosis condition. The changes of WT1 gene and MRD before treatment and 3, 9 and 12 months after treatment were observed in both groups; the changes of WT1 gene and MRD before and after treatment were compared in the children with different therapeutic plans; the relationships of clinicopathological features with WT1 gene expression and positive rate of FMM-MRD were analyzed in AML children. Spearman correlation coefficient was used to analyze the relationships of WT1 gene expression and positive rate of FCM-MRD with the prognosis of AML children; the Kaplan-Meier survival curve was drawn to analyze the effects of WT1 gene expression and positive rate of FMM-MRD on the recurrence of AMLchildren and their correlations; the receiver operating characteristic (ROC) curve was drawn to analyze the efficiencies of single detection with WT1 gene and FMM-MRD and combined detection in predicting prognosis of AML children; the relationships of WT1 gen and MRD with FLT3 ITD/TKD mutation were analyzed in AML children.

Results The WT1 expression levels and positive rates of FCM-MRD at 9 and 12 months after treatment in the good prognosis group were significantly lower than those in the poor prognosis group (P<0.05); the WT1 gene expression level and positive rate of FCM-MRD in children with DAH chemotherapy regimen were lower than those in children with DAE chemotherapy regimen, while the rate of good prognosis was higher than thatin children with DAE chemotherapy regimen, but there were no significant differences between children with different chemotherapy regimens (P>0.05); the WT1 gene expression and the positive rate of FCM-MRD were significantly correlated with white blood cell count, FAB typing, bone marrow primitive cells, and cytogenetic grouping in AML children (P<0.05). Spearman correlation coefficient analysis showed the WT1 gene expression and positive rate of FCM-MRD were significantly negatively correlated with prognosis of AML children (P<0.05); the Kaplan-Meier survival curve validation showed that overall survival (OS) and progression free survival (PFS) in children with high expression of WT1 were significantly lower than those in children with low expression of WT1 (χ²=4.215, 9.530; P=0.040, 0.002), and OS and PFS in children with positive FCM-MRD were also significantly lower than those in children with negative FCM-MRD (χ²=5.144, 6.381; P=0.023, 0.012); the Spearman correlation coefficient analysis showed that the WT1 gene expression was significantly negatively correlated with OS and PFS in AML children (P<0.05); the ROC curve showed that the area under the curve of WT1 combined with FCM-MRD was significantly higher than that of single indicator detection, with a sensitivity of 88.89% and a specificity of 87.50%; the Spearman correlation analysis showed that there were no significant correlations of WT1 gene expression and positive rate of FCM-MRD with FLT3 ITD/TKD mutation (P>0.05).

Conclusion The expression level of WT1 and the positive rate of FCM-MRD show specific changes in AML children with different prognosis, and are strongly correlated with the prognosis of AML children. Combined detection of the two indicators can effectively predict the prognosis of AML children.