'Epigenetics', the term that is used for the study of heritable changes in gene function that occur without a change in the DNA sequence, has become a significant area of research. As a consequence of this emerging field, our concepts founded upon genetics alone have been blurred and the way researchers think about heredity has changed. Epigenetic mechanisms such as DNA methylation, histone modifications ('histone code'), chromatin modifiers, RNA interference as well as their effects in gene activation and inactivation are increasingly understood to be more than 'sideline players' in phenotype transmission and development, which consequently impacts significantly on our study of disease states such as cancer.