Epigenetic system: a pathway to malignancies and a therapeutic target.

Cancer cells possess both genetic and epigenetic alterations that dysregulate essential cellular processes, leading to disordered cell proliferation and differentiation. Oncogenes and tumor suppressor genes have been found to be activated and inactivated, respectively, in malignant cells. Epigenetic regulation of the genome is mediated by interactions between DNA methylation, chromatin, and modifications of histones and various transcriptional regulators. Recent studies have shown that some components of the epigenetic system as well as epigenetically mutated genes are diagnostic and therapeutic targets in cancer. We discuss the molecular basis of the epigenetic mechanism in association with the development of cancer.