肾母细胞瘤患儿p73基因的表达及其甲基化研究

Relationship between mRNA expression and promoter methylation status of p73 gene in peripheral blood among children with Wilms' tumor

摘要:

目的：探讨肾母细胞瘤患儿血液中p73基因的转录表达、启动子甲基化状态及二者之间关系。方法：收集45例肾母细胞瘤患儿为病例组，以健康体检或因其他原因就诊的性别、年龄匹配的15例（排除肿瘤等恶性疾病）儿童为对照组。采集两组儿童外周血，运用实时荧光定量PCR（qRT-PCR）和甲基化特异性PCR (MSP)法检测p73基因转录表达水平及其启动子甲基化状态，并分析病例组中p73基因的表达及甲基化与临床资料的关系，及p73基因的甲基化对其转录表达的影响。结果：病例组中p73 mRNA的相对表达量（3.2±0.9）高于对照组（1.6±1.1），差异有统计学意义（P<0.01）；病例组p73基因甲基化阳性率（20%）低于对照组 (73%)，差异有统计学意义（P<0.01）。病例组中甲基化p73 mRNA的相对表达量大于非甲基化p73 mRNA的相对表达量（P<0.01），且大于对照组中甲基化p73 mRNA的相对表达量（P<0.01）；非甲基化p73 mRNA的相对表达量在两组间差异无统计学意义（P=0.810）。结论：肾母细胞瘤外周血中p73基因启动子的异常甲基化是其基因表达调节方式之一，并与肾母细胞瘤的发生发展有关；发生甲基化的p73基因在肾母细胞瘤中有可能充当癌基因的角色，转录水平的过度表达与其甲基化状态有关。

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.