Breast and ovarian cancers share many features, including genetic predisposition caused by mutations in BRCA1/2. Epithelial ovarian cancer is heterogeneous and associated with poor survival relative to breast cancer. Utilizing comprehensive biobanks, genomics methods and in vitro model systems we aim to improve our understanding of tumour evolution, heterogeneity and therapy response. Events underlying malignant transformation are poorly characterised in ovarian cancer, but accumulating evidence suggests that a majority of ovarian cancers arise in the Fallopian tube epithelium.