Global DNA hypomethylation in cancer cells has been suggested to be attributed to one of the following causes: (1) a discoordination between DNA replication in cancer cells and DNMT-1 activity; (2) a natural selection of hypomethylated DNA patterns accompanying overexpression of specific oncogenes or genomic instabilities that facilitate cancer cell growth and expansion; or (3) a consequence of chromatin dysregulation and nuclear disorganization that occur during cancer progression [36]. Here, DNMT1 is linked to cancer.