ADGRA2 and neoplasm: For example, endosialin (CD 248), the expression of CD248 in the tumor endothelium, is dramatically higher (5‐ to 20‐fold) than that in the endothelium of normal tissues.[84] G‐protein‐coupled receptor 124 (GPR124) regulates the proliferation of human umbilical vein endothelial cells (HUVEC).[85] Morevoer, the activation of GPR124 is associated with cell‐to‐cell contacts during capillary morphogenesis.[85] In the TME, the GPR124 is highly expressed in the ECs.