**Abstract**

Early diagnosis and intervention are some of the longstanding challenges associated with ovarian cancer, which is the leading cause of gynecologic cancer mortality. While the majority of patients who present with advanced stage disease at time of diagnosis will initially respond to traditional combination platinum and taxane-based chemotherapy in conjunction with cytoreductive surgery, approximately 70% will ultimately recur due to chemoresistance within the first two years. Intratumor heterogeneity is proposed to be a leading factor in the development of chemoresistance and resultant poorer outcomes for those with recurrent or advanced stage disease. Both inherent and acquired mechanisms of chemoresistance are postulated to be a result of alterations in gene expression, also known as epigenetic modifications. Therefore, epigenetic therapy is a pivotal avenue which allows for reversal of chemoresistance in cancer through the targeting of aberrant mutations. In this chapter, we discuss how these epigenetic modifications prove to be promising targets in cancer therapy leading to heightened drug sensitivity and improved patient survival outcomes.

**Keywords:** cancer therapy, epigenetics, histone deacetylase inhibitors (HDACis), DNA methyltransferase inhibitors (DNMTis), tumor microenvironment
