On the other hand, despite the well-documented anti-tumor functions of M1 macrophages and pro-tumoral functions of M2 macrophages, the prognostic value of CD163+ and CD206+ M2 macrophages was controversial in different cohorts of patients with GBM, emphasizing an unmet need to decipher the exact function of specific TAM subtypes in GBM (20, 99); however, limited by conventional approaches, hurdles exist to distinguish and characterize TAM subpopulations in GBM. This evidence concerns the gene MRC1 and glioblastoma.