骨髓增生异常综合征患者分泌型卷曲相关蛋白2基因启动子区甲基化状态研究

 目的　了解骨髓增生异常综合征（MDS）患者Wnt／β-catenin信号转导通路中拮抗基因分泌型卷曲相关蛋白2（SFRP2）的甲基化状态，研究其甲基化状态与染色体核型及生存的关系。方法　应用甲基化特异性聚合酶链反应（MSP）对43例MDS患者的骨髓或外周血SFRP2基因启动子区甲基化状况进行检测，并以70例门诊普通患者外周血检测结果为对照，同时对部分患者进行随访。结果　43例MDS患者中检出10例（23.3 %）SFRP2甲基化，均为半甲基化状态，70例正常对照中未检出SFRP2的甲基化，组间差异有统计学意义（χ2＝17.86，P＜0.0001）。10例SFRP2甲基化的样本中， 5例来自骨髓，5例来自外周血，其中难治性贫血（RA）3例，伴环形铁粒幼细胞增多性难治性贫血（RAS）1例，难治性血细胞减少伴多系发育异常（RCMD）2例，原始细胞过多难治性贫血（RAEB）3例，MDS不能分类（MDS-U）1例。单因素分析结果显示不同性别、年龄、染色体核型、样本来源（骨髓／外周血）、危险度（WPSS≤2及>2）间甲基化率差异无统计学意义，疾病进展与稳定组甲基化率差异亦无统计学意义（均P＞0.05）。20例患者有染色体核型结果，16例进行了密切随访，3例转为急性髓系白血病（AML），死亡11例中2例为SFRP2甲基化阳性，但甲基化与非甲基化组间生存率差异无统计学意义（χ2＝0.022，P＞0.05）。结论　MDS患者中SFRP2基因存在较高的甲基化修饰，这可能是MDS发病的分子机制之一；在MDS SFRP2的甲基化检测中，外周血有较好的代表性；该组患者例数较少，尚未发现甲基化与临床预后间的相关性。

Methylation status in the promoter region of secreting frizzled related protein 2 gene in patients with myelodyplastic syndrome

Objective To investigate the methylation status in the promoter region of secreting frizzled related protein 2 (SFRP2) gene in patients with myelodyplastic sydrome (MDS) and to initially explore the relationship between the methylation of this gene and prognosis/survival time.Methods MSP method was applied to examine the promoter methylation of SFRP2 gene in 43 bone marrow or peripheral blood samples of MDS patients.As controls,70 normal peripheral blood samples from volunteers of general outpatients were examined.Then some of the patients were followed up.Results In 43 patients of MDS,10 samples (23.3 ％)showed SFRP2 gene methylation,and all of them were semi-methylation status.In 70 controls,no sample showed SFRP2 gene methylation.The frequency of SFRP2 gene methylation in MDS patients was significantly higher than that in controls (x2 =17.86,P ＜0.0001).Of the 10 SFRP2 gene methylation samples,5 were bone marrow samples and 5 were peripheral blood samples.In this group of patients,3 patients were diagnosed as RA,1 patient was diagnosed as RAS,2 patients were diagnosed as RCMD,3 patients were diagnosed as RAEB and 1 patient was diagnosed as MDS-U.There was no significant difference between the different sample source (bone marrow or peripheral blood) for the results of the methylation status (x2 =0.912,P ＞0.05).Either no significant difference between the different sex,age,type,chromosome and WPSS score (all P ＞0.05).The progress of disease didn' t influence the methylation rate (P ＞0.05).16 patients accepted follow-up and 11patients died,3 patients went to AML.2 died patients showed SFRP2 gene methylation.The survival analyses showed no relationship between the methylation of this gene and survival time (x2 =0.022, P ＞0.05).Conclusion In this MDS group,there is a high level of methyl-modification in SFRP2 gene.The methylation of SFRP2 may be one of the molecular mechanisms that contribute to the progress of patients with MDS.The peripheral blood sample maybe a better substitute in detection of SFRP2 with MDS.