Epigenetics is the study of heritable changes caused by mechanisms other than DNA sequence alterations. Epigenetic mechanisms are now well established as playing an important role in cancer etiology. We have hypothesized that epigenetic variability in peripheral blood DNA would predict cancer risk or prognosis. We are testing this hypothesis by assessing epigenetic changes across the genome in ovarian and breast cancer patients. We anticipate this will lead to improvements in understanding of breast and ovarian cancer etiology, disease and outcome. Upon completion of this study we will have identified a set of cancer related epigenetic biomarkers – since these are evaluated in ready available tissue (blood), there is excellent potential for use in routine screening programs.