Iron plays a fundamental role in cell life and its concentration in living organisms is precisely regulated. Different molecules for iron storage and transport are used to maintain its intracellular homeostasis which is often altered in cancer cells. Specifically, recent studies have demonstrated that in breast cancer cells, the expression/activity of several iron-related proteins, such as ferritin, hepcidin and ferroportin, is deregulated and that these alterations may have a prognostic impact in patients with breast cancer. Moreover, molecules that regulate iron metabolism could become therapeutic targets. This review focuses on recent findings on iron metabolism particularly in breast cancer and on the development of new biomarkers that may be used in the clinical routine for the diagnosis, prognosis and management of cancer-associated anemia as well as for monitoring personalized treatments.