Epigenetic processes include molecular pathways that modify the DNA or the proteins that are associated with DNA (i.e. histones), thereby affecting how the genetic information is used to maintain cellular states. Thus epigenetics plays an important role in normal biology and disease. When deregulated, epigenetic processes could contribute to disease development and progression. Since embryonic stem cells (ESCs) and cancer cells share the capacity to divide indefinitely, our proposal aims to understand the epigenetic requirements for such capacity. We have found that a particular epigenetic process, which we previously linked to cancer progression, may contribute to regulation of DNA replication in human ESCs. We have also discovered how epigenetic processes could in novel ways exert control over metabolic state of the cell. Finally, we have discovered how chromatin – the complex of DNA and histones – at specific sets of gene families is differentially compacted in differentiated cell types vs. human ESCs. Altogether, we are providing novel insights into the functions of various epigenetic processes and how they may differ in stem cells vs. other normal and cancer cell types.