DNMT1 and neoplasm: MiR-340 is a recently recognized tumor suppressor which targets and decreases expression of DNMT1, EZH2 and H3K27me3, leading to promoter hypomethylation and expression of E-cadherin as well as decreased expression of mesenchymal markers (N cadherin, vimentin and fibronectin) in TNBC cells [42].