中文摘要：

目的：筛选直肠癌组织异常表达的miRNAs。方法：采用miRCURY“基因芯片（v．14．0）分析直肠癌组织和邻近非肿瘤组织之间差异表达的miRNA，设定平均上升或下降倍数大于2倍和P值小于0．05为差异标准。结果：88个miRNAs表达显著上调，其中46个基因已证实在结直肠癌组织中表达升高；40个miRNAs表达显著下调，其中15个已报道在结直肠癌组织中表达异常降低。实时定量PCR（RT-qPCR）结果显示：6个表达上调的miRNAs在直肠癌组织中也异常高表达，与基因芯片结果比较，表达水平相差从-11．88％至39．09％；同样6个表达下调的miRNAs在肿瘤组织中也呈低表达，与基因芯片结果比较，表达水平相差从1．35％至29．35％。基因芯片与RT，qPCR两方法分析的结果呈高度相关（r=0．96，P〈0．01）。结论：相对于混合样本（结直肠癌）miRNA表达谱，直肠癌miRNA表达谱呈现出明显的特异性；同时鉴定了一系列新的异常表达的miRNAs。

英文摘要：

Objective： To identify aberrantly expressed miRNAs in rectal cancer. Methods： We used the miKCUKY Array LNA microRNA chip （v.14.0） to evaluate miRNA expression levels between rectal cancer tissues and adjacent non-tumor tissues; an average change more than 2-fold （and P value less than 0.05） was set as a cutofflevel. All 6 paired rectal cancers were classified pathology stage C or D. Results： Eighty-eight miRNAs were up-regulated and 46 miRNAs have been reported in colorectal cancer; 40 miRNAs were down-regulated in rectal cancers and 15 miRNAs have been reported in colorectal cancer. To compare the relative miRNA expression levels as measured by RT-qPCR and chip analysis, we analyzed expression levels of these miRNAs in the cancer tissues. l-he results showed that miRNA expression （increased or decreased） in the paired benign and tumor tissue wasconsistent between the two methods in all cases. Expression levels of 6 up-regulated miRNAs （by chip analysis compared to RT-qPCR） varied in a range from -11.9% to 39.1% .Expression levels of 5 down-regulated miRNAs varied in a range from 1.4% to 29.4%. The Pearson correlation of relative miRNAs expression levels was analyzed by cDNA array versus RT-qPCR, and found to be 0.96 （P〈0.01）. Conclusion： miRNA profile in rectal cancer showed unique characteristics, and identified a series of new, aberrantly expressed miRNAs.