Epigenetics and Cancer

Anomalous epigenetic signaling plays a critical role in cancer. The best-known epigenetic modifications are DNA methylation and histone post-transcriptional modifications, including methylation, acetylation, ubiquitination, and phosphorylation. Histone methylation is another well-studied histone modification. It is linked to both transcriptional activation and repression. Histone tails can become methylated at several lysine and arginine residues. The histone code determines its structure and function. Thus, the histone code will differ depending on the region of the chromatin, the cell type, the tissue type, and the external conditions of a cell. One of the most important epigenetic routes to carcinogenesis involves the aberrant pattern of histone modifications at gene promoters. The potential role of sirtuins as proteins promoting cell proliferation is also supported by the use of sirtuin inhibitors. These are thought to possess anticancer activity and to induce senescencelike growth arrest.