DNMT1 and breast cancer: Furthermore, Zhou et al (2008) showed that deletion of 120 amino acids of N-terminal region inhibits LBH589 (clinically relevant HDAC inhibitor)-induced DNMT1 ubiquitination in MDA-MB-231 cells, indicating that impairment in regular ubiquitination leads to genomic hypermethylation in breast cancer cell lines (Zhou et al. 2008).