ABSTRACT
Epigenetics, the study of mitotically and meiotically heritable changes in gene expression not involving changes in DNA sequence, involves three interacting molecular mechanisms: DNA methylation, histone modification, and RNA-mediated gene silencing (Figure 25.1) [1]. Epigenetic mechanisms are known to show stability as well as flexibility in regulating gene expression during mammalian development [2]. Although each of the three epigenetic mechanisms is physiologically important, it is thought that of the three mechanisms, DNA methylation is predominant in controlling gene expression [3] and the most stable in modulating the transcriptional plasticity of mammalian genomes [4]. A disruption in one of the three epigenetic mechanisms can lead to inappropriate expression or silencing of genes, resulting in disease. It has been predicted that epigenetics, although a new field, will have an enormous impact on medicine, offering new opportunities for the diagnosis and treatment of complex clinical disorders [5]. Previous chapters have discussed the roles and applications of each of the three molecular epigenetic mechanisms in relation to cancer. The field of cancer epigenetics is evolving rapidly on several fronts. This chapter discusses possible future directions in research on cancer epigenetics.
