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

目的：探讨CDH1基因启动子所在5'-CpG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'-CpG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GenBank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。

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

Objective To investigate the correlation between the abnormal methylation of 5'-CpG islands har-boring cadherin 1 (CDH1) gene promoter in and the development of clinical condition, pathological changes and postop-erative prognosis. Methods A total of 184 patients with colorectal cancer resection of primary colorectal cancer in De-partment 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'-CpG 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 GenBank. Results The diameter of methyla-tion 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 signifi-cant difference (P<0.01). Tumor differentiation degree in methylation group (high differentiation 14.0%, medium differ-entiation 36.0%) was significantly lower than that in the non-methylation group (high differentiation 40.8%, medium dif-ferentiation 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 (methyl-ation group:11.6%in stageⅠ, 11.6%in stageⅡ, 37.2%in stageⅢ, 39.5%in stageⅣ;non-methylation group:27.6%in stageⅠ, 32.7%in stageⅡ, 20.4%in stageⅢ, 19.4%in stageⅣ), 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 can-cer (RR=28.5, P<0.001). Conclusion Colorectal cancer patients with higher aberrant methylation of 5'-CpG of CDH1 gene promoter of suspension cells in abdominal lavage have higher malignancy, more metastasis and worse prognosis.