中文摘要：

目的分析抑癌候选基因NDRG2在人类结肠肿瘤组织中的表达情况。方法收集30例患者的结肠癌组织及其正常组织，提取总RNA，应用半定量反转录-聚合酶链反应（RT-PCR）检测NDRG2 mRNA的表达水平。为进一步分析NDRG2蛋白质的表达水平，分别提取30例组织的总蛋白，应用蛋白质印迹和免疫组织化学（免疫组化）技术检测其NDRG2的蛋白表达水平。结果RT-PCR结果显示，30例结肠癌组织中，有12例的NDRG2 mRNA表达明显降低。蛋白印迹结果显示，30例结肠肿瘤组织中有12例NDRG2蛋白水平明显下降，与RT-PCR结果一致。免疫组化结果显示，正常组织及肿瘤组织中NDRG2阳性率分别为90．0％（27／30）和53．3％（16／30），组间阳性表达率差异有统计学意义（P〈0．05），NDRG2的表达与患者的年龄、性别、淋巴结转移、浸润深度、Dukes分期无明显相关关系（P〉0．05），而与肿瘤组织分化级别相关，高、中分化组NDRG2阳性表达率高于低分化组（P〈0．05）。结论NDRG2在某些结肠癌组织中呈低表达，而且其表达与结肠癌的分化程度有关，提示其可能对结肠癌的发生或发展有重要的作用。这为研究结肠癌的发病机制提供了进一步的线索。

英文摘要：

Objective To analyze the expression level of candidate tumor suppressor gene N- Myc downstream-regulated gene 2 （NDRG2） in human colon cancer. Methods Thirty samples of colon cancer tissues with matched normal colon tissues were collected. The NDRG2 mRNA level was detected by semi-quantitive RT-PCR and the NDRG2 protein level was examined by Western blot and immunohistochemistry. Results Twelve samples of colon cancer tissues had low NDRG2 mRNA level and low protein level. The positive rates of NDRG2 in normal tissues and the tumorous colon tissues were 90.0%（27/30） and 53.3%（16/30）by immunohistochemistry respectively. There was a significant difference between two groups （P〈0.05）. The NDRG2 expression was not correlated with age, sex, metastasis of lymph node, depth of infiltration, as well as the Dukes staging（P〉0.05）, while it was correlated to the histology grading. The positive rate of NDRG2 in the well- and moderate- differentiation group was higher than that in the poor-differentiation group （P〈0.05）. Conclusion The expression of NDRG2 is low in some colon cancer tissues, which indicates that the low level of NDRG2 expression may be engaged in the development of colon cancer.