RAC2 and glioblastoma: Astrocyte subpopulation B (combined from all three brain regions) is mostly correlated with the mesenchymal glioblastoma gene signature, as the enriched genes in this gene set (e.g., Scpcp1, Rac2, Blcrb, Mrc2, Cd14, and C5ar, among others) are upregulated in this subpopulation.