儿童急性淋巴细胞白血病CASP8AP2基因启动子甲基化水平及其临床意义  

Clinical Significance of CASP8AP2 Gene Methylation in Childhood Acute Lymphoblastic Leukemia

作　　者：刘飞飞[1] 刘潇[1] 王凯玲[1] 李伟京[1] 邓国仁[2] 高超[1] 赵晓曦[1] 吴敏媛[1] 崔蕾[1] 李志刚[1] 

机构地区：[1]首都医科大学附属北京儿童医院血液肿瘤中心,儿科重大疾病研究教育部重点实验室,儿科学国家重点学科,儿童血液病与肿瘤分子分型北京市重点实验室,北京100045 [2]美国加利福尼亚大学旧金山医学院泌尿系,旧金山ca94101

出　　处：《中国实验血液学杂志》2015年第1期6-11,共6页Journal of Experimental Hematology

基　　金：国家自然科学基金资助项目(81170504和81200392);北京市自然科学基金资助项目(7112051和7152054);北京市卫生系统高层次卫生技术人才培养计划(2011-3-049)

摘　　要：目的:研究半胱氨酸-天冬氨酸蛋白酶8相关蛋白2(Caspase 8 associated protein 2,CASP8AP2)基因在儿童急性淋巴细胞白血病(acute lymphoblastic leukemia,ALL)初诊和缓解时的启动子区Cp G位点的甲基化水平,及其与儿童ALL临床特征、预后的关系。方法:收集2007年8月到2010年3月于我院就诊的109例ALL患儿的初诊DNA样本,及其中94例患儿的缓解期DNA标本。DNA样本经硫化处理后,用本研究组建立的甲基化荧光法,测定CASP8AP2基因转录起始点上游的两个关键Cp G位点(-1189和-1176)的甲基化水平。结果:初诊患儿CASP8AP2基因启动子区上述2个位点的平均甲基化水平为(71.1±1.7)%,高于缓解患儿的样本(64.2±21.2%)(P=0.008)。受试者工作特征曲线下面积为0.687(P=0.024),说明这2个位点的甲基化水平具有一定的预测复发的能力。以76.9%为分界点,将初诊患儿分为高甲基化组(49例)和低甲基化组(60例)。高甲基化患儿更容易出现复发(20.4%vs 6.7%)(P=0.044),5年无复发生存率明显低于低甲基化组(Log rank,P=0.033)。初诊高甲基化与巩固治疗前微小残留病(minimal residual disease,MRD)高水平相关(P=0.011)。诱导缓解治疗后MRD≥10-4的34例患儿中,高甲基化患儿的复发率明显高于低甲基化患儿(8/16例vs 3/18例,P=0.038)。结论:CASP8AP2基因启动子区-1189和-1176两个Cp G位点的异常高甲基化可能与儿童ALL的发病相关,且高甲基化患儿的预后较差;将上述位点的甲基化水平与诱导缓解治疗结束时MRD水平相结合,能够更好地预测复发。Objective ： To study the methylation level in the promoter of caspase 8 associated protein 2 （ CASP8AP2 ） gene between samples at diagnosis and in complete remission, and to investigate its relationship with clinical features and prognosis in children with acute lymphoblastic leukemia （ALL）. Methods： Diagnostic DNA samples from 109 newly diagnosed children with ALL admitted from August 2007 to March 2010, and 94 ALL children in CR （ complete remission） among them were collected. Bisulfite modification and MethyLight method established by our research team were used to determine the methylation level of the two key CpG sites （at - 1189 and - 1176） of the promoter of CASP8AP2 gene. Results： The average methylation level of the two CpG sites in newly diagnosted samples was higher than that in CR samples （71. 1%±1.7% vs 64. 2%± 21. 2% ） （P = 0. 008）. Analysis with receiver operating characteristic （ROC） curve showed that the area under curve was 0. 687 （P = 0. 024）, indicating that the methylation level of the two CpG sites was able to predict relapse efficiently to some extent, 76.9% was chosed as a cutoff value to divide the patients into high methylation group （49 patients ） and low methylation group （60 patients ）. The incidence of relapse in high methylation group was higher than that in low methylation group （ 20.4 % vs 6.7 % ） （ P = 0.044 ）, five year relapse free survival in high methylation group was also lower than that in low methylation group （ Log rank, P = 0. 033）. Furthermore, high methylation at new diagnosis were correlated with high level of minimal residual disease （MRD） before consolidation therapy （P = 0. 011 ）. In the 34 children with MRD ≥ 10^-4 at the end of induction remission, the relapse rate of high methylation patients was significantly higher than that of low methylation patients （8/ 16 vs 3/18） （P =0. 038）. Conclusion：The abnormal hypermethylation of the two CpG sites （at - 1189 and - 1176） of the promot

关 键 词：儿童急性淋巴细胞白血病 半胱氨酸-天冬氨酸蛋白酶8相关蛋白2 DNA甲基化 微小残留病 复发 

分 类 号：R733.71[医药卫生—肿瘤]