GFAP and glioblastoma: Al-Dalahmah et al. characterized the microenvironment of GBM using snRNA-seq and clustered GFAP-positive reactive astrocytes into three subtypes: protoplasmic astrocytes (AST1, highly expressing SLC1A2/3/4, CPE, CPG5), reactive astrocytes expressing oligodendrocyte and neuronal genes (AST2, high expression of PLP1, RPL13A, RPL31, FTL, BCYRN1), and reactive astrocytes expressing inflammatory genes (AST3, high expression of S100B, CP, C3, CD44, CHI3L1/2, CLU) [54].