Overview

• Princeton-led researchers show metastatic tumor cells co-opt erythroblast island macrophages, diverting iron away from red blood cell precursors.
• The hijacked macrophages fail to support the final maturation step of red blood cells, worsening anemia by stalling enucleation.
• Tumor cells activate a GATA1-driven program to produce hemoglobin/β-globin, helping them tolerate the bone marrow’s low-oxygen conditions.
• Depleting these iron-recycling macrophages in mice impaired breast cancer growth in bone, indicating a functional role in metastatic progression.
• Similar iron-handling macrophages and elevated β-globin were observed in human bone metastases from breast, lung and kidney cancers, pointing to broader relevance and early-stage therapeutic opportunities.