Despite the low relative abundance of pericytes within the GBM microenvironment, spatial expression analysis of the mural cell marker genes PDGFRβ and ACTA2 in a human spatial transcriptomics GBM dataset (Fig. S1D) demonstrated the strategic positioning of pericytes in close proximity to blood vessels with easy access to the malignant parenchyma. The gene discussed is ACTA2; the disease is glioblastoma.