Chapter 42 – Personalized Epigenetics

Personalized epigenetics identifies epigenetic alterations in individual patients as a predisposition for diseases or, if a disease is already present, their influence on disease progression and therapeutic outcome. This review gives a brief overview of different epigenetic layers that will impact personalized medicine, focused on DNA and histone modifications. Examples of how epigenetic drivers affect the course of diseases will be discussed with an emphasis on cancer; however, many of these concepts are applicable to other diseases. In contrast to genetic mutations, alterations in the epigenome are much more dynamic. Environmental influences or even aging constantly modify existing epigenetic traits. Furthermore, therapies produce a considerable selection pressure in epigenetic marks that can contribute to therapy resistance. The increasing knowledge of the dynamic epigenetic landscape along with the possibility to reverse epigenetic modifications makes this an attractive field for drug development. However, several examples show that the outcome of epigenetic interventions is context dependent. Therefore, new therapeutic principles have to carefully consider the interactions between epigenetic writers, readers, erasers, and chromatin modifying complexes. To keep pace with the huge technological advances and the rapidly increasing knowledge in biomedicine, new collaborations have to be implemented to include personalized epigenetics in clinical decision-making.