PECAM1 and central nervous system cancer: We selected a panel of six antibodies validated for formalin-fixed paraffin-embedded (FFPE) tissue sections to identify endothelial cells (E; CD31), pericytes (P; α-SMA), macrophages (Mφ)/microglia (M; CD68), glioma cells (G; GFAP), proliferating cells (Ki-67) and CXCL12+ cells alongside 4′,6-diamidino-2-phenylindole (DAPI) as nuclear stain (Fig. 3c).