Epigenetics, microRNAs and cancer: an update

Genetics alone cannot explain disease: in fact, people sharing the same DNA sequence (monozygotic twins) often present different levels of disease penetrance. The term epigenetics partially explains this phenomenon. Originally introduced to name the causal interactions between genes and their products, bringing the phenotype into being, it was subsequently used to define the heritable gene expression changes not related to any alteration in DNA sequence. Epigenetics has captured the attention of biomedical research, from immunology, neurology, cardiovascular to oncology; particularly in the fields of DNA methylation, histone modifications, and chromatin remodeling. Since the initial characterization of methylation in human tumors, the epigenetic research has gone far introducing recently also the preliminary descriptions of epigenomes of human cells. MicroRNAs are a class of small noncoding RNAs in many diseases including cancer. This chapter focuses on the link between epigenetics and miRNAs in cancer.