CD47 and glioblastoma: The disruption of the SIRPα-CD47 signaling axis is efficacious against various brain tumors, including GBM, primarily by inducing tumor phagocytosis, and even in the absence of phagocytizing macrophages (Ccr2 RFP/RFP), microglia are effector cells of tumor cell phagocytosis in response to anti-CD47 blockade [9].