食管鳞癌患者围手术期外周血抑癌基因甲基化水平的动态变化及临床意义

摘要

目的 研究食管鳞癌患者围术期外周血抑癌基因甲基化的动态变化,探讨血浆游离DNA甲基化水平评估荷瘤状态的参考价值.方法 采用定量甲基化特异性生物聚合酶链式反应技术对76例食管鳞癌患者术前1d、手中及术后第7天外周血游离DNA中APC、RARβ2、CDH1、p16INK4α、RASSF1A 5个抑癌基因的甲基化状态进行检测.同时选取60例年龄相匹配的健康志愿者外周血浆DNA作为对照.结果 术前1d外周血中APC、RARβ2、CDH1、p16INK4α、RASSF1A 基因的甲基化率分别为42.11%(32/76)、63.16%(48/76)、63.16%(48/76)、71.05%(54/76)、50.00%(38/76);术中为64.5%(49/76)、73.7%(56/76)、75.0%(57/76)、82.9%(63/76)、56.6%(43/76);术后第7天为5.3%(4/76)、4.0%(3/76)、6.6%(5/76)、3.9%(3/76)、1.3%(1/76);与术前相比术中外周血DNA甲基化率均上升,其中APC基因甲基化的两个时点的变化差异有统计学意义(P=0.006); 而RARβ2、CDH1、p16INK4α、RASSF1A的变化差异无统计学意义(P =0.163、0.114、0.083、0.416).术后第7天5个基因DNA甲基化率与术前相比均显著下降(P=0.000).结论 食管癌患者外周血抑癌基因高甲基化,在手术刺激后DNA甲基化率明显上升,提示肿瘤可能存在逃逸现象,手术后患者DNA甲基化率下降,提示随着肿瘤实体的去除,肿瘤细胞或肿瘤核酸片段在外周血中随之消失.%Objective To investigate the perioperative dynamic changes oftumor suppressor gene methylation in plasma of patients with esophageal squamous cell carcinoma (ESCC) and its significance. Methods Real-time methylation-specific PCR (MSP) technique was used to detect methylation status of 5 tumor suppressor genes: APC, RARp 2, CDH1, pl6INK4α and RASSF1A in peripheral blood 1d before, during and 7d after operation in 76 ESCC patients and 60 age- matched healthy subjects (controls). Results Methylation rates of APC, RARp 2, CDH1, p16INK4α and RASSF1 Agenes in peripheral blood were 42.11% (32/76), 63.16% (48/76), 63.16% (48/76), 71.05% (54/76) and 50.00% (38/76) respectively Id before operation and those were 64.5% (49/76), 73.7% (56/76), 75.0% (57/76), 82.9% (63/76) and 56.6% (43/76) respectively during operative, and those were 5.3% (4/76), 4.0% (3/76), 6.6% (5/76), 3.9% (3/76) and 1.3% (1/76) 7d after operation. Methylation rates of peripheral blood DNA were all higher intraoperatively than that preoperatively and the change of APC methylation rate was statistically significant (P=0.006), and those for RARp 2, CDH1, p16INX4α and RASSF1A were not statistically significant (P=0.163, 0.114, 0.083 and 0.416, respectively). DNA methylation rates were significantly decreased 7d after operation and all the differences were statistically significant(P=0.000). Conclusion Hypermethylation oftumor suppressor genes APC, RARp 2, CDH1, p16INK4α and RASSFlAex-ists in patients with ESCC.