DNA damage repair in ovarian cancer: unlocking the heterogeneity

Treatment for advanced ovarian cancer is rarely curative; three quarters of patients with advanced disease relapse and ultimately die with resistant disease. Improving patient outcomes will require the introduction of new treatments and better patient selection. Abrogations in the DNA damage response (DDR) may allow such stratifications. A defective DNA-damage response (DDR) is a defining hallmark of high grade serous ovarian cancer (HGSOC). Indeed, current evidence indicates that all HGSOCs harbour a defect in at least one major DDR pathway. However, defective DDR is not mediated through a single mechanism but rather results from a variety of (epi)genetic lesions affecting one or more of the five major DNA repair pathways. Understanding the relationship between these pathways and how these are abrogated will be necessary in order to facilitate appropriate selection of both existing and novel agents. Here we review the current understanding of the DDR with regard to ovarian, and particularly high grade serous, cancer, with reference to existing and emerging treatments as appropriate.