Epigenetics and Tumor Suppressor Genes

Abstract

Genes which protect cells from malignant transformation were referred to as tumor suppressor genes (TSGs). Since the first description of TSG, Rb (retinoblastoma susceptibility gene), a myriad of genes have been identified as TSGs. These TSGs play critical roles in cell cycle control, apoptosis, DNA damage detection and repair, adhesion, metastasis, senescence, and carcinogen detoxification. Loss function of TSGs may cause uncontrolled cell growth and cancer. TSGs may be inactivated by different mechanisms during carcinogenesis. In addition to genetic changes, epigenetic aberration plays an important role in inactivation of TSGs. Epigenetics is described as heritable changes in gene expression that do not involve a change in the DNA sequence (Berger et al., 2009). DNA methylation and histone modification are two predominant epigenetic changes. More recently, non-coding RNAs were regarded as new epigenetic regulation tools. The purpose of this chapter is to describe the effects of epigenetic modification on TSGs.