Ludwig Institute for Cancer Research Sep 4 2025 Breast cancers frequently spread to the bone, establishing tumors that are largely impervious to treatment and are associated with poor patient prognoses. A deficiency in the oxygen-carrying capacity of the blood, or anemia, is among the most common complications of these common metastases. Though such anemia was thought to stem from the tumor's disruption of bone marrow-the body's manufacturing hub for all blood cells, including its oxygen-