SIRPA and glioblastoma: Macrophage-mediated phagocytosis of tumor cells via blockade of the anti-phagocytic CD47-SIRP interaction using anti-CD47 antibodies has shown potential in preclinical xenografts of various human malignancies 23, 24 Moreover, traversing the BBB for mAb-mediated treatment of GBM is another challenge that largely precludes the systemic approach for mAb therapy in most patients with GBM 25.