Abstract: 【Objective】 We used the DNA methylation microarrays to investigate the hypermethylated genes in colorectal cancer and adjacent normal mucosa. 【Method】 DNA was extracted from six pairs of CRC and adjacent normal mucosa and sonicated into fragments ranging in size from 300-1000 bp

followed by methylated DNA Immunoprecipitation analysis and then sent to NimbleGen for Microarray hybridization according to their standard protocol. The hybridized array is then scanned and the resulting image analyzed. The biologic functions were analyzed by bioinformatics methods. In addition

preliminary validation studies were done in six pairs of samples by MSP (methylation-specific PCR). 【Results】 Compared with the normal tissues

there are 2 296 genes were hypermethylated

in which 293 hypermethylated genes were unreported. All these genes were randomly distributed on all the chromosomes. According to gene ontology analysis

the genes involved in some physiological processes which play important roles in the cell division and the development of tumor are methylated

such as DNA repair

cell cycle and invasion et c. Preliminary validation

the Opcml in thirty top-ranking genes was shown hypermethylated in six pairs of colorectal cancer (CRC) and adjacent normal mucosa. 【Conclusions】 High density DNA methylation microarrays is an effective method for screening aberrantly methylated genes in CRC.