Unlike prostate cancer screening, breast cancer screening has failed to reduce the incidence of patients presenting with metastatic disease, a phenomenon referred to as de novo metastatic breast cancer (dnMBC). This discrepancy in screening outcomes has led to the hypothesis that these tumours are prone to spread by nature. In this project we will investigate the clinical and molecular features of these tumours to gain insight into why they behave the way they do, hopefully leading to the identification of important pathological processes that can be targeted in the future.