DNMT1 and colorectal cancer: As further evidence of procainamide's specificity for DNMT1, procainamide failed to lower genomic 5-methyl-2'-deoxycytidine levels in HCT116 colorectal cancer cells when DNMT1 was genetically deleted, but significantly reduced genomic 5-methyl-2'-deoxycytidine content in parental HCT116 cells and in HCT116 cells in which DNMT3b was genetically deleted [185].