RNA-seq data from our laboratory show that GPR56 is the most abundantly expressed aGPCR in patient-derived GBM cells (Figure 1A), whereas single-cell SMART-seq data from the Allen Brain Atlas suggest that GPR56 expression is low in neurons and moderate in astrocytes and OPCs from normal brain tissue (Figure 1B). Here, ADGRG1 is linked to glioblastoma.