ACTA2 and neoplasm: Intriguingly, in some GBM samples, HMGA2-labelled cells have close proximity to tumor microvessels, or even positive for α-SMA/ACTA2 (smooth muscle α-actin), CD146, CD248 and PDGFRB (platelet-derived growth factor receptor beta), which are pericyte (the smooth muscle cell for microvessels) biomarkers (Figure 2D, Supplementary Figure S2A-S2C).