CD33 and neoplasm: By analysing RNAs found in extracellular vesicles (EVs) derived from microglia that had interacted with GBM, Maas et al. [103] recently found that GBM-interacting microglia down-regulate genes involved in the detection of tumour cells (sialic acid-binding immunoglobulin-like lectin-H (Siglec-H), CD33 and GPR34) and tumour-derived metabolic by-products (Gpr183, Adora3, Il6Ra, Cx3cr1, P2ry12, P2ry13, Csf1r, and Csf3r) [103].