Abstract：OBJECTIVE: To investigate the mRNA expression and promoter methylation status of p73 gene in the peripheral blood of children with Wilms' tumor (WT), and their relationship. METHODS: Forty-five children with WT were selected as the case group, and 15 sex- and age- matched children (without malignancies) who visited the hospital for physical examination or other reasons were selected as the control group. Peripheral blood was collected from both groups. Real-time quantitative PCR and methylation-specific PCR were used to determine the mRNA expression level and promoter methylation status of p73 gene. Their relationship with clinicopathological features and the effect of promoter methylation on mRNA expression of p73 gene were analyzed in the case group. RESULTS: The relative quantity (RQ) of p73 mRNA in the case group was significantly higher than in the control group (3.2±0.9 vs 1.6±1.1; P<0.01). The positive rate of p73 gene promoter methylation in the case group was significantly lower than in the control group (20% vs 73%; P<0.01). In the case group, the RQ of p73 mRNA was significantly higher in children with methylated p73 gene promoter than in those with unmethylated p73 gene promoter (P<0.01). In children with methylated p73 gene promoter, the RQ of p73 mRNA was significantly higher in the case group than in the control group (P<0.01). In children with unmethylated p73 gene promoter, there was no significant difference in RQ of p73 mRNA between the case and control groups (P=0.810). CONCLUSIONS: Aberrant promoter methylation of p73 gene in peripheral blood is one of the gene expression regulations in children with WT, and it is related to the onset and development of WT. The p73 gene may play a role as oncogene in WT patients with p73 gene promoter methylation and mRNA overexpression is associated with promoter methylation status of p73 gene.
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