DNMT1 and neoplasm: This concept led to the development of DNMT1 inhibitors (DNMT1i), based on the premise that inhibition of DNMT1 mediated methylation may reactivate tumor suppressor genes that have been silenced by methylation.8, 9, 10, 11 The most common approach to inhibit DNMT1 is through the use of cytidine analogs that deplete DNMT1 and thereby inhibit DNA methylation.12