Overview of techniques involved (e.g. 'omics')

2. Genomics

2.5. Epigenetics

Epigenetics is the study of how genes can be turned on or off, or modulated (e.g. turned up or down), without any changes to their DNA sequence (i.e. without a mutation). The study of epigenetics is growing and is important in our understanding of the risk of getting a disease, how a disease will progress, or how it will respond to treatment.

Epigenetic changes are made by chemical changes in the DNA. They can occur in response to changes within the body, or to external factors such as UV light, diet, tobacco use or stress.

Epigenetic changes also happen when there are changes to the protein molecules that bind to DNA. Many of these proteins are involved in making epigenetic changes, and in ‘reading’ the resulting DNA. The pharmaceutical industry is getting more and more interested in such proteins, because they may be suitable new targets for medicines. Indeed, several medicines that influence epigenetic changes are already in clinical development and some have a marketing authorisation (such as ‘azacytidine’ for myelodysplastic syndromes)

Many cancers are related to epigenetic changes for specific genes. The epigenetic regulation of gene expression is called ‘gene silencing’. Silencing means that a cell can prevent a certain gene to be expressed. Methods to silence genes are increasingly used to produce therapeutics that can combat cancer and diseases. An example is the epigenetic silencing of the ‘GSTP1’ gene (the gene’s expression is reduced). This gene is likely to be a cause of prostate cancer.

Most progress to date in the discovery of medicines within epigenetics has been for cancer treatments. For example for breast and liver cancers, leukaemias and Hodgkin’s lymphoma.