Aberrant promoter methylation and gene amplification in colorectal cancer

To identify new markers for colorectal cancer we scrutinized the methylation status by methyl-CpG immunoprecipitation followed by global methylation profiling on a CpG island microarray, as altered expression could drive genomic and chromosomal instability observed in these tumors. We show for the first time hypermethylation of MMP9, DNMT3A, and LIG4 in CRC which was confirmed in two independent ethnic CRC patients groups. Hypermethylation of the LIG4 promoter is a new mechanism to control ligase IV expression. It may represent a new epigenetic marker for colorectal cancer independent of known markers. Methylation profiling in 16 tumors of colorectal cancer patients compared to matched normal tissue of these patients