We took advantage of the development of an isogenic cell line obtained from the human colon cancer cell line HCT-116, where the DNA methyltransferases 1 (DNMT1) and 3B (DNMT3B) genes have been genetically disrupted by homologous recombination (double knockout cells, DKO) [26]. Here, DNMT3B is linked to malignant colon neoplasm.