DNMT1 and neoplasm: We employed the Combined Bisulfite RestrictionAnalysis (COBRA) assay to monitor themethylation status of P16INK4A, a tumor suppressor genereactivated by DNMT inhibition/deletion, and Long Interspersed Nucleotide Element 1 (LINE-1) repeats, a well-establishedsurrogate measure of global DNA methylation. HCT-116 cells were treated for 10 days, with media changes and freshcompound additions every 3 days to allow for passive DNA demethylationand dilution of the DNA methylation signal. Decitabine (5-azadC) was used as a positive control.