Modifying the epigenome as a therapeutic strategy in myelodysplasia

The term epigenetics refers to a number of biochemical modifications of chromatin that, without altering the primary sequence of DNA, have a role in genomic regulation and in particular gene expression control. These modifications can occur at the DNA level (i.e., DNA methylation), and affect the chromatin protein scaffold (i.e., histone code modifications), among several others. The study of these modifications is a very active area of research both at the basic and clinical levels. Clinical interest in these epigenetic alterations stems mainly from two observations. First, detection of specific epigenetic alterations could be used to develop cancer biomarkers (e.g., for the early detection or prognostication of cancer). Second, most epigenetic alterations are reversible both in vitro and in vivo, leading the way to the development of new anticancer therapies. This review focuses on the current clinical information regarding different forms of epigenetic therapy in patients with myelodysplastic syndromes (MDS). Basic aspects of DNA methylation or histone code alterations are not covered in detail in this review.