To further investigate the role of promoter hypermethylation in miR190-mediated CDKN1B transcription downregulation, 5-aza-2′-deoxycytidine (5-Aza), a DNA methyltransferase (DNMT) inhibitor, was used to inhibit genomic DNA methylation in human BC cells [30]. This evidence concerns the gene DNMT1 and breast cancer.