MSR1 and neoplasm: Surprisingly, GBMs also possess a similar iron-replenishing network composed of hemorrhaged erythrocytes and phagocytosing TAMs that maintains iron homeostasis within a tumor; i.e., immunohistochemical, DAB and Prussian blue staining of GSC-driven GBM tissues showed that at least a part of CD204+ TAMs phagocytose the hemorrhaged erythrocytes and store iron [11].