Moreover, another single-cell study revealed immunosuppressive CD163+HMOX1+ microglia in human GBM samples that expressed tumor-associated macrophage genes such as CD163, CCL4, APOE, and HLA-DRA and showed a significant enrichment of pathways involved in antigen-processing and cytokine signaling similar to the mouse glioma-associated microglial cells. Here, APOE is linked to central nervous system cancer.