Cancer of the ovary is one of the leading causes of cancer deaths among Canadian women. Most of the deaths occur in patients that have very aggressive cancers, and in whom standard drug treatment no longer works. The reasons why such resistance emerges are largely unknown. Here, I will study the most aggressive type of ovarian cancer, with the goal of better understanding how it develops. These new insights may help predict which treatments will be effective in a given patient, and pave to way to the identification of new therapeutics to cure this highly lethal cancer.