Contrary to human homologues DKK1 and DKK2, whose silencing by CGI hypermethylation is indicated both in colon cancer cell lines and gastrointestinal tumors [33,39-41], Dkk1 downregulation in mice has been suggested to occur through factors independent of DNA hypermethylation [26]. This evidence concerns the gene DKK2 and colonic neoplasm.