中文摘要：

目的：微小RNA（microRNA）异常在肿瘤发生发展中起重要作用，本研究探讨microRNA mir219在肝细胞癌中的异常甲基化和异常表达，可能参与肝细胞癌的发生发展过程。方法：采用pyrosequence、TA克隆测序等方法检测正常肝组织、肝细胞癌细胞株和肝癌标本中mir219上游预测启动子区域甲基化，Taqman实时定量RT-PCR测定肿瘤组织表达。结果：与正常肝脏组织相比，肝癌细胞株、肝癌标本中mir219上游预测启动子区域中茎环区和上游1kb区域的CpG岛存在高度甲基化。肝癌细胞株、肝癌标本中mir219表达显著下调，与其异常甲基化相关。结论：肝癌中微小RNA mir219茎环序列上游1094bp区域存在启动子区异常甲基化，表达下调。提示mir219异常可能在肝细胞癌发生发展中起重要作用，是潜在的抑癌基因。

英文摘要：

Objective：To study the aberrant methylation in putative promoter region of MicroRNA mir219 and the methylation correlated expression down-regulation in HCC （hepatocellular carcinoma）, and explore the potential role of mir219 in HCC. Methods：In HCC tumor sample and cell line, the methylation status of putative promoter region of mir219 by pyrosequence and TA sequencing were detected; and the expression detected by Taqman real time RT-PCR. Results：There were aberrant methylation in the CpG Island lkb upstream and stem-loop sequence of mir219 in HCC, and the mir219 transcription was also significant downregulated in HCC cell line. Conclusion：The 1094 bp upstream and stem-loop sequence was putative promoter region of mir219, which was aberrantly methylated in HCC and transcription down-regulated in HCC. It indicated its potential role in HCC development.