MicroRNAs and cancer epigenetics.

The term epigenetics refers to all heritable changes in gene expression that are not associated with concomitant alterations in the DNA sequence. Reversible DNA methylation and histone modifications are the hallmarks of epigenetic gene regulation. MicroRNAs (miRNAs) are a recently discovered category of noncoding RNAs with important regulatory functions. Aberrancies in both the epigenetic and in the miRNA regulation of genes have been documented in cancer. An increasing number of studies are showing that the abnormalities of the epigenome and of the miRNome are not independent and could be explained both by an epigenetic regulation of miRNA expression and by miRNA control on components of the epigenetic machinery. A deeper understanding of this correlation could lead to new therapeutic avenues.