GFAP and neoplasm: Thus, the number of cells corresponding to some tumor cells, some activated microglia, as well as all endothelial cells and some pericytes of mesenchymal origin (vimentin), or astrocytes and glioma cells (GFAP), or macrophages and microglia (Iba1), increased dramatically, suggesting that many cell types important for glioma pathology and response may be quantitatively underestimated by conventional immunostaining.