Immunofluorescence analysis of surgical tumor specimens from human patients with different grades of gliomas showed that a large population of GBM-associated CD68+ macrophages robustly expressed CD206 and CD163 (Fig. 1a, b) and relatively expressed CD86 at a lower level (Supplementary Fig. 1), while only small population of CD68+ macrophages or microglia cells expressed CD206 in normal brains (Supplementary Fig. 1). Here, MRC1 is linked to glioblastoma.