GFAP and glioblastoma: In addition to exhibiting human GBM histopathology features—including pseudopalisading necrosis, microvascular proliferation, and positive S100-β and GFAP staining—this QPP GEMM also recapitulated the immune cell populations in human GBM, which consists of predominantly immunosuppressive myeloid cells with smaller lymphocyte populations [72,73].