SIRPA and glioblastoma: We examined the expression of known phagocytosis-inhibitory receptors, such as signal regulatory protein α (SIRP-α), sialic acid binding Ig like lectin 10 (Siglec-10), and programmed cell death 1 (PD-1) in GBM tumors from two murine GBM-bearing mice (Supplementary Fig. 2c).