MRC1 and glioblastoma: Furthermore, as compared with normal saline and Fe3O4-siNC, Fe3O4-siPD-L1, Fe3O4-siPD-L1@M-BV2 and Fe3O4-siPD-L1@M-BV2 + magnet significantly reduced the number of Iba-1+CD206+ cells (M2 type microglia) in drug-resistant GBM tissue.