胃癌患者血清RASSF1A基因启动子区甲基化检测

Ras相关结构域家族1A（RASSF1A）基因是近年发现的新型抑癌基因，其启动子区甲基化可能与胃肠道肿瘤的发生、发展密切相关。目的：检测胃癌患者血清RASSF1A基因启动子区甲基化情况，探讨其在胃癌早期诊断和预后评估中的可能作用。方法：以甲基化特异性聚合酶链反应（MSP）检测47例胃腺癌患者、30例胃良性病变患者和30名健康对照者的血清RASSF1A基因启动子区甲基化情况，其中16例胃腺癌患者同时留取手术切除癌组织、癌旁组织标本以及术前、术后血标本行对照研究。结果：胃腺癌患者血清RASSF1A基因启动子区甲基化率为34．0％（16／47），显著高于胃良性病变患者（3.3％，1／30）和健康对照者（0％）（P〈0．01）。16例胃腺癌组织中5例（31．2％）检测到RASSF1A基因启动子区甲基化，其中4例（80．0％）术前、术后血清标本均检测到RASSF1A基因启动子区甲基化。血清RASSF1A基因启动子区甲基化与胃癌患者性别、年龄、肿瘤分化程度、有无转移以及血清癌胚抗原（CEA）水平均无相关性。结论：血清RASSF1A基因启动子区甲基化检测可望为胃癌的早期诊断和预后判断提供依据。

Detection of Serum RASSF1A Gene Promoter Methylation in Patients with Gastric Cancer

Background: Ras association domain family 1A (RASSF1A) gene is a novel tumor suppressor gene, and methylation of its promoter region might be an important mechanism in the development and progress of gastrointestinal cancer. Aims: To identify the promoter methylation status of serum RASSF1A gene in patients with gastric cancer, and to investigate its potential use in the early diagnosis and prognosis assessment of gastric cancer. Methods: Promoter methylation status of serum RASSF1A gene was determined by methylation-specific polymerase chain reaction (MSP) in 47 patients with gastric adenocarcinoma, 30 patients with benign gastric disease and 30 healthy controls. In 16 patients with gastric adenocarcinoma, the resected cancerous tissues, paracancerous tissues as well as the pre- and post-operative blood samples were collected for controlled study. Results: The positivity rate of promoter methylation of serum RASSF1A gene in gastric adenocarcinoma patients (34.0%, 16/47) was significantly higher than that in benign gastric disease patients (3.3%, 1/30) and in healthy controls (0%) (P<0.01). In 16 gastric cancerous tissues, 5 (31.2%) had promoter methylation of RASSF1A gene. Of them 4 patients (80.0%) had promoter methylation of serum RASSF1A gene in both pre- and post-operative blood samples. No correlation was found between promoter methylation status of serum RASSF1A gene and gender, age, tumor differentiation, metastasis and serum carcinoembryonic antigen (CEA) level in patients with gastric adenocarcinoma. Conclusions: Methylation of promoter region of serum RASSF1A gene is a promising biomarker for the early diagnosis and prognosis assessment of gastric cancer.