中文摘要：

背景与目的：MicroRNA（miRNA，miR）是一类可负性调控基因表达的非编码小RNA，能通过与mRNA分子相互作用阻遏蛋白质翻译或导致RNA降解；且在肿瘤的发生、发展中扮演着重要的角色。本研究旨在探讨microRNA-338～3p（miR-338—3p）在结直肠癌与癌旁组织中差异表达状况及其与临床病理特征和预后之间的关系。方法：选取南方医院2008年9—11N间经手术切除的原发性结直肠癌标本40例，完善相关病理资料；常规抽提肿瘤及对照癌旁组织中总RNA，应用实时荧光定量PCR检测标本中miR-338～3p表达状况，并分析其与临床病理特征及预后的关系。结果：40例结直肠癌与癌旁组织相比，miR-338-3p表达明显下调（0．1226±0．0873VS0．9058±0．4105），差异有统计学意义（P〈0．01）；miR-338—3p表达水平与肿瘤TNM分期（P=0．031）、浸润深度（P=0．001）以及分化程度（P=0．042）有关；miR-338-3p表达水平越低，其3年无进展生存率及总生存率越低。结论：MiR-338—3p可能作为“抑癌基因”参与了结直肠癌的发生、发展，并可作为结直肠癌预后判断的新的生物标志物。

英文摘要：

Background and purpose： MicroRNAs （miRNA, miR） are a class of small non-coding RNAs that control gene expression by targeting mRNA and triggering either translation repression or RNA degradation. Recent studies showed that miRNA played an important role in the development and progression of tumors. This study aimed to investigate the microRNA-338-3p （miR-338-3p） differential expression patterns in carcinoma and adjacent non-tumorous tissues and their relationship with clinicopathological features and prognosis in colorectal carcinoma. Methods： Forty colorectal carcinoma and adjacent non-tumorous specimens, which were diagnosed and operated in Nanfang Hospital, were collected respectively and the total RNA was isolated routinely. The miR-338-3p expression pattern was detected by real-time quantitative polymerase chain reaction. The relationship between the expression of miR-338-3p and clinicopathological features and prognosis was analyzed. Results： The expression of miR-338-3p was significantly down-regulated in colorectal carcinoma tissues as compared with those in the adjacent non-tumorous tissues （0.122 6 ~： 0.087 3 vs 0.905 8 ＋ 0.410 5, P〈0.01）, and the expression level was positively correlated to an advanced TNM stage （P=0.031）, local invasion （P=-0.001） and differentiation （P=0.042）. The three-year progression- free survival and overall survival were lower along with the lower expression level of miR-338-3p. Conclusion： The expression absence of miR-338-3p may play an important role in the development and progression of colorectal carcinoma. MiR-338-3p can be a new biological marker in predicting the prognosis of colorectal carcinoma.