GRM4 and neoplasm: For example, GRM4 belongs to the GRM protein family and plays an important role in the regulation of ion channels, neuronal excitability, and neurotransmitter release,[30] Indeed, overexpression of GRM4 can significantly inhibit the proliferative, migratory, and invasive abilities of tumor cells, while GRM4 can also suppress osteosarcoma growth through a non-cell-autonomous mechanism by regulating IL23.[31] Its role in asthma may involve neuroinflammatory aspects of the disease.