CpG island methylation in colorectal cancer. Homo sapiens

To globally define methylation-’prone’ and -’protected’ CpG islands in cancer, we analyzed the methylation status of 23,000 CpG islands of the human genome in 19 colorectal carcinoma samples as well as normal colon using our previously described methyl-CpG immunoprecipitation (MCIp) technique (Gebhard et al. 2006; Schilling and Rehli 2007). This method enriches for highly CpG methylated DNA that can be directly applied to fluorescent labeling and oligonucleotide microarray hybridization without an additional amplification step. Overall design: CpG-methylated genomic DNA was enriched using methyl-CpG immunoprecipitation (MCIp). On each microarray, the enriched material from colorectal carcinoma samples was compared to the enriched material from normal colon to identify aberrantly methylated regions.

为在全基因组层面定义癌症中易发生甲基化与受甲基化保护的CpG岛（CpG islands），我们采用此前报道的甲基CpG免疫沉淀（methyl-CpG immunoprecipitation, MCIp）技术，对19例结直肠癌样本及正常结肠组织中人类基因组的23000个CpG岛的甲基化状态展开分析（Gebhard等，2006；Schilling与Rehli，2007）。该方法可富集高CpG甲基化的DNA，无需额外扩增步骤即可直接用于荧光标记及寡核苷酸微阵列杂交。实验整体设计：采用甲基CpG免疫沉淀（MCIp）富集CpG甲基化的基因组DNA。在每张微阵列上，将结直肠癌样本的富集产物与正常结肠组织的富集产物进行比对，以识别异常甲基化区域。