Meanwhile, knocking down of DNMT1 in colon cancer cells significantly increased the ability of 5-Aza-CdR to increase expression of CDKN2A, indicating that DNMT1 may work additively or synergistically with other members of DNMT in regulating DNA methylation (Robert et al., 2003). This evidence concerns the gene DNMT1 and malignant colon neoplasm.