CD47 and central nervous system cancer: Of note, CD47, which is known to be upregulated in glioma stem cells, binds to SIRPα on the surface of macrophages to exert a “don't eat me” signal, thus contributing to immune evasion of the tumor cells by preventing phagocytosis by macrophages (Gholamin et al, 2017; Hu et al, 2020).