尿路上皮癌外周血死亡相关蛋白激酶的甲基化与纯合性缺失状态及其意义

Promoter methylation and homozygous deletion of death-associated protein kinase in blood of patients with urothelial carcinoma

目的:研究启动子区甲基化及纯合性缺失对死亡相关蛋白激酶(DAPK)表达及尿路上皮癌(UC)生物学行为的影响。方法:使用甲基化特异性PCR(MSP)检测45例UC患者外周血循环DAPK启动子区甲基化情况;使用DifferentialPCR技术检测DAPK纯合性缺失情况,分析DAPK启动子区甲基化及纯合性缺失与肿瘤分级分期的相关性。使用RT-PCR技术检测相应肿瘤的DAPK表达情况。结果:MSP提示10例出现DAPK启动子高甲基化(22%);DifferentialPCR提示6例出现启动子区纯合性缺失(13%);RT-PCR提示15例样本mRNA表达下调或缺失。统计学分析提示DAPK启动子高甲基化及纯合性缺失与DAPK表达下调或缺失明显相关(P<0.01),启动子高甲基化与肿瘤浸润性明显相关(P=0.002),启动子纯合性缺失与肿瘤分级明显相关(P=0.003)。结论:DAPK启动子区高甲基化与纯合性缺失是导致DAPK表达异常的重要因素。

Objective To investigate the effects of death-associated protein kinase （DAPK） promoter methylation and homozygous deletion on the expression of DAPK in blood of patients with urothelial carcinoma （UC） and on the biological behavior of UC. Methods The methylation special PCR （MSP） and the differential PCR were used to detect the promoter methylation and homozygous deletion, respectively, in 45 patients with UC. The RT-PCR was used to detect the expression of DAPK. The correlations of DAPK promoter methylation and homozygous deletion and the grade and staging of rumor were analyzed. Results 10 cases （22%） had promoter hypermethylation, and 6 cases （13%） had promoter homozygous deletion, 15 cases （34%） had low expression or deletion of DAPK mRNA. DAPK promoter methylation and homozygous deletion were significantly associated with the low expression or deletion of DAPK （P 〈 0.01 ）, promoter methylation was significantly （P = 0.002） associated with invasive UC and promoter homozygous deletion was significantly （P = 0.003） associated with the grade of UC. Conclusions The promoter methylation and homozygous deletion of DAPK are important factors that influence the expression of DAPK.