中文摘要：

目的探讨甲基化CpG岛扩增联合代表性差异分析（MCA/RDA）方法在筛查人非小细胞肺癌（NSCLC）组织中高甲基化修饰序列的应用。方法以92对NSCLC和癌旁对照组织DNA为研究对象,应用MCA/RDA方法筛查肺癌组织DNA中高甲基化修饰的CpG岛序列。应用反转录聚合酶链反应（RT-PCR）和甲基化特异性PCR（methylation-sensitive PCR,MSP）技术,分析胰岛素样生长因子结合蛋白（IGFBP-4）基因启动子区CpG岛的甲基化修饰与基因表达的相关性。结果获得5个经Slot Blot验证在肺癌组织中高甲基化修饰的CpG岛序列（IGFBP-4、KLK10、ADAM23、GADD45G和DUOX1）。甲基化抑制剂5-aza-2＇-deoxycytidine处理NSCLC细胞可明显上调IGFBP-4基因的表达。在41例（44.6%）癌组织中检测到IGFBP-4表达水平显著低于癌旁对照组织。47例（51.1%）癌组织检测到IGFBP-4高甲基化显著高于癌旁组织的检出率（16.3%,15/92;P〈0.001）。IGFBP-4高甲基化与基因表达呈负相关（r=-0.396,P〈0.001）。IGFBP-4高甲基化与TNM分期（P=0.013）和淋巴结转移（P=0.022）相关。结论应用MCA/RDA方法筛查到5个在NSCLC组织中高甲基化修饰的CpG岛序列,并证实IGFBP-4启动子区CpG岛的高甲基化可能通过抑制基因的表达参与了NSCLC的发生。

英文摘要：

Objective To identify the promoter hypermethylation of CpG islands in human non-small-cell lung cancer（NSCLC）.Methods Methylated CpG island amplification（MCA） coupled with Representational Difference Analysis（RDA） were used to isolate methylated CpG islands in 92 NSCLC tumor tissues and adjacent normal tissues.RT-PCR and methylation-sensitive PCR（MSP） were used to examine the correlation between CpG islands methylation and gene expression of IGFBP-4.Results Five sequences that corresponded to promoter CpG islands of IGFBP-4,KLK10,ADAM23,GADD45G and DUOX1 genes were isolated and confirmed by Slot Blot hybridization in NSCLC specimens.Weak expression of IGFBP-4 in NSCLC cells was increased after the treatment with 5-aza-2′-deoxycytidine.The expression of IGFBP-4 was significantly downregulated in 41（44.6%） tumor tissues compared with corresponding normal tissues.IGFBP-4 hypermethylation was detected in 47（51.1%） tumor tissues,significantly higher than normal tissues（16.3%,15/92,P0.001）.IGFBP-4 expression and its promoter hypermethylation were negatively correlated（r=-0.396,P0.001）.Moreover,IGFBP-4 hypermethylation was associated with advanced stage（P=0.013） and lymph metastasis（P=0.022）.Conclusion Five hypermethylated CpG islands were isolated by MCA/RDA method in NSCLC specimens and epigenetic silencing by hypermethylation of the IGFBP-4 CpG-rich promoter region is likely to be involved in the progression of NSCLC.