The fact that ACKR1+ endothelial cells, which are involved in chemokine trafficking in innate immunity, were the most metabolically active cells in the younger ER+ cohort, together with their enriched signaling nodes with PVLs, suggests an important immunomodulatory role within the younger ER+ tumor microenvironment (Fig 7b). Here, ACKR1 is linked to neoplasm.