To clarify the role of Ndn in metastasis, the aims of the current study are threefold: first, and most critically, to confirm that Ndn is a germline modifier of patient outcome in human breast cancer; second, to explore how germline variation in mouse Ndn modifies its functionality in order to more clearly understand its role in metastasis susceptibility in this model system; and third, to functionally characterize Ndn in order to define a mechanism by which it impacts metastasis. Here, NDN is linked to breast carcinoma.