IDH2 and astrocytoma (excluding glioblastoma): According to evidence of decreased immune cells in IDH-mutated glioma, even IDH-mutant astrocytoma grade 4, previously known as IDH mutant GBM, has been demonstrated to have a lower proportion of tumor-associated microglia and macrophages than IDH-wildtype GBM, with predominant M1 polarization [44].