胃和结直肠腺癌患者血清RASSF1A基因启动子异常甲基化检测及其临床意义

摘要

目的 研究胃和结直肠腺癌患者血清RASSF1A基因启动子区域的甲基化状态及其临床意义.方法采用甲基化特异性聚合酶链反应(MSP)技术,检测47例胃腺癌患者、45例结直肠腺癌患者、60例胃肠道良性病变患者及30例健康志愿者血清RASSF1A基因启动子区域的甲基化状态,并同时检测25例进行手术的胃腺癌、结直肠腺癌患者的肿瘤组织和邻近正常组织的RASSF1A基因的甲基化状态,分析其与临床病理参数之间的相关性.结果47例胃腺癌患者血清RASSF1A基因启动子区域异常甲基化16例,检出率为34.0％,45例结直肠腺癌患者血清RASSF1A基因启动子区域异常甲基化13例,检出率为28.9％,而30例胃部良性疾病患者的检出率为3.3％ (1/30),30例结直肠良性疾病患者的检出率为6.7％ (2/30),30例健康志愿者中检出率均为0(0/30),差异有统计学意义,均为P ＜0.01.25例进行手术的胃、结直肠腺癌患者血清中的RASSF1A启动子异常甲基化状态与之匹配的对应组织中的检出率是一致的,术前和术后血清中的基因甲基化检出率也是一致的.RASSF1A启动子异常甲基化与患者的性别、年龄、肿瘤分期、手术治疗和血清中的CEA水平无关.结论RASSF1A启动子异常甲基化在胃和结直肠腺癌患者血清中有着较高的检出率,有望成为胃和结直肠腺癌诊断和预后的分子标志.%Objective To detect the hypermethylation of RASSF1A promoter in serum DNA of the gastric and color-ectal adenocarcinoma patients and to analyze its correlation with clinicopathological features. Methods Serum DNA was extracted from peripheral blood of 47 primary gastric adenocarcinoma patients, 45 primary colorectal adenocarcinoma patients, 60 benign gastrointestinal disease patients and 30 healthy donors. In 25 gastric and colorectal adenocarcinoma patients who later underwent surgical therapy, promoter methylation of RASSF1A was compared in primary tumor, adjacent normal tissue and postoperative serum. The methylation of RASSF1A promoter was determined by mthylation-specific PCR, and the correlation between methylation and clinicopathological parameters was statistically analyzed. Results The frequencies of RASSF1A promoter hypermethylation in gastric (34. 0% , 16/47) and colorectal (28. 9% , 13/45) ade-nocarcinoma patients were significantly higher than those of benign gastric (3. 3% , 1/30) and colorectal (6. 7% , 2/ 30) disease patients (P＜0. 001). And no hypermethylation appeared in healthy donors. Hypermethylation of RASSF1A was consistent in serum samples and paired primary tumor, and RASSF1A promoter methyaltion level was consistent in paired pre-and postoperative serum samples. We also found that RASSF1A promoter hypermethylation was not associated with gender, age, tumor differentiation grade, surgical therapy or serum CEA level. Conclusion RASSF1A promoter is frequently hypermethylated in serum DNA of primary gastric and colorectal adenocarcinoma patients, and it may be a promising novel biomarker for the diagnosis and prognosis of gastric and colorectal adenocarcinomas.