Briefly, glioblastoma cells initially secrete low levels of the chemokine CCL2 to attract microglia cells chemotactically, and then also microglia cells start to release EVs containing CCL2 [56], attracting even more microglial cells into the tumor, promoting tumor progression and development, as stated in [55,57,58]. The gene discussed is CCL2; the disease is glioblastoma.