AIM DNA methylation is a fundamental biologic process of genomes and is a candidate for pharmacological manipulation that might have important therapeutic advantages. Thus, DNA methyltransferases (DNMTs) appear to be ideal targets for drug intervention. MATERIALS & METHODS To develop a new generation of DNMT inhibitor, we analyzed the ability of peptides to selectively inhibit certain DNMT1-incuding complexes. RESULTS Our study demonstrates that the disruption of DNMT1/CFP1-including complexes increases the efficiency of chemotherapeutic treatment on established tumors in mice. CONCLUSION Our data opens a promising and innovative alternative to the development of DNMT inhibitors.