GFAP and neoplasm: GEMM pontine, subependymal, and intraventricular tumor areas had similar numbers of CD45+, CD8+, and CD163+ cells, and there were no differences in all staining except for GFAP (Figure 5A, B, and D), where there was significantly increased GFAP expression in the subependymal tumor compared to the primary tumor (Figure 5C).