Genome-wide methylation analysis of AOM/DSS-induced colon tumors

Genome-wide methylation analysis was performed by methylated DNA immunoprecipitation (MeDIP)-CpG island (CGI) microarray analysis to identify candidate CGIs specifically methylated in mouse colon tumors associated with colitis. We sucessfully identified 23 candidate CGIs methylated in tumors. Two samples were analyzed by MeDIP-CGI microarray. One is a pool of two AOM/DSS-induced colon tumors in BALB/c mice and another is a pool of two normal colonic epithelial cell samples obtained from untreated BALB/c mice by the crypt isolation technique. The pool of normal colonic epithelial cell samples was used as reference. Dye-swaps were not perfromed. The methylation statuses of CGIs identified by microarray were confirmed by another method, methylation-specific PCR.