CDH1基因甲基化状态与结直肠癌临床病理特征及预后的相关性研究

Correlation between CDH1 gene methylation status and clinical pathological characteristics and prognosis of colorectal cancer

目的探讨CDH1基因启动子所在5’-Cp G岛的异常甲基化与临床病情发展、病理变化及术后预后的相关性。方法选取2013年1~12月在我院肿瘤科进行结直肠癌切除术的原发性结直肠癌患者184例,其中甲基化组86例,非甲基化组98例,所有入选患者由专人进行跟踪随访。检测CDH1基因启动子所在5’-Cp G岛的异常甲基化,通过全基因组扩增技术对修饰后的DNA进行扩增,根据Gen Bank基因库设计CDH1基因甲基化特异性引物及CDH1基因非甲基化特异性引物。结果甲基化组肿瘤直径为(6.5±2.1)cm,大于非甲基化组的(3.2±2.2)cm,甲基化组肿瘤浸润性所占比例54.7%,高于非甲基化组的42.9%,差异均有显著统计学意义(P<0.01);甲基化组肿瘤分化程度(高分化14.0%,中分化36.0%)低于非甲基化组(高分化40.8%,中分化45.9%%),差异有显著统计学意义(P<0.01);甲基化组淋巴转移率为67.4%、远处转移率为31.4%,高于非甲基化组的21.4%和17.3%,差异均有统计学意义(P<0.05);甲基化组临床TNM分期更晚(甲基化组:Ⅰ期11.6%,Ⅱ期11.6%,Ⅲ期37.2%,Ⅳ期39.5%;非甲基化组:Ⅰ期27.6%,Ⅱ期32.7%,Ⅲ期20.4%,Ⅳ期19.4%),差异均有显著统计学意义(P<0.01);非甲基化组患者生存率(89.5%)高于甲基化组患者(68.7%),差异有统计学意义(P<0.05)。Cox比例风险模型结果显示,腹腔灌洗液悬浮细胞CDH1基因甲基化是原发性结直肠癌患者术后预后生存率的独立危险因素(RR=28.5,P<0.01)。结论原发性结直肠癌患者腹腔灌洗液悬浮细胞CDH1基因甲基化程度提高,恶性程度高,预后差。

Objective To investigate the correlation between the abnormal methylation of 5’-Cp G islands harboring cadherin 1(CDH1) gene promoter in and the development of clinical condition, pathological changes and postoperative prognosis. Methods A total of 184 patients with colorectal cancer resection of primary colorectal cancer in Department of Oncology in our hospital were selected and divided into methylation group(n=86) and non-methylation group(n=98) from January to December 2013. All patients were selected and followed up by specially-assigned person.The abnormal methylation of 5’-Cp G islands harboring cadherin 1(CDH1) gene promoter was detected, and modified DNA genome was amplified by whole genome amplification technology. CDH1 gene methylation specific primers and CDH1 gene non-methylation specific primers were designed according to Gen Bank. Results The diameter of methylation group was significantly larger than that of non-methylation group [(6.5±2.1) cm vs(3.2±2.2) cm], and the proportion of tumor invasion was significantly higher than that of non-methylation group(54.7% vs 42.9%), with statistically significant difference(P<0.01). Tumor differentiation degree in methylation group(high differentiation 14.0%, medium differentiation 36.0%) was significantly lower than that in the non-methylation group(high differentiation 40.8%, medium differentiation 45.9%), with statistically significant difference(P<0.01). The rate of lymph node metastasis and the distant metastasis of methylation group were significantly higher than those of the non-methylation group(67.4% vs 21.4%,31.4% vs 17.3%, P<0.05). The clinical TNM staging was later in methylation group than non-methylation group(methylation group: 11.6% in stage Ⅰ, 11.6% in stage Ⅱ, 37.2% in stage Ⅲ, 39.5% in stage Ⅳ; non-methylation group: 27.6%in stage Ⅰ, 32.7% in stage Ⅱ, 20.4% in stage Ⅲ, 19.4% in stage Ⅳ), the differences were statistically significant(P<0.01). The survival rate of patients in non-methylation group was significantly higher than those in methylation group(89.5% vs 68.7%, P<0.01). Cox proportional hazard model results showed that CDH1 gene methylation of suspension cells in intraoperative abdominal lavage was an independent risk factor for prognosis in patients with primary colorectal cancer(RR=28.5, P<0.001). Conclusion Colorectal cancer patients with higher aberrant methylation of 5’-Cp G of CDH1 gene promoter of suspension cells in abdominal lavage have higher malignancy, more metastasis and worse prognosis.