Dacogen is indicated for treatment of patients with myelodysplastic syndrome (MDS). It is a chemical analogue of cytidine, a nucleoside present in DNA and RNA. Cells in the presence of Dacogen incorporate it into DNA during replication and RNA during transcription. The incorporation of Dacogen into DNA or RNA inhibits methyltransferase thereby causing demethylation in that sequence. This adversely affects the way that cell regulatory proteins are able to bind to the DNA/RNA substrate.