Malignant Transformation and Epigenetics

The human epigenome plays a central role in cancer. The epigenome regulates stable gene expression patterns and is linked to the abnormal phenotype of a cancer cell. Epigenetic modifiers include enzymes that change DNA methylation patterns, alter posttranslational modifications of histones, and control chromatin structure and function. For decades aberrant epigenetic patterns have been observed in cancer tissue, frequently associated with irregular expression of epigenetic regulators. Here, we present some novel evidence that links epigenetics and cancer. We summarize recent studies that report the occurrence of genetic mutations of a chromatin-modifying enzyme in human cancer. Thus in some cancers, genetic changes may contribute directly to epigenetic alterations. In addition, we provide evidence based on mouse studies in which genetic manipulation (resulting in depletion or overexpression of an epigenetic modifier) can influence cancer incidence. Understanding the role of epigenetics can provide insights into the pathogenesis of cancer, and may lead to the development of biomarkers, improve prognosis, and support the development of novel molecular targets in cancer therapies.