GPR158 and glioblastoma: Recent studies have shown that GPR158 may quantitatively characterize the malignant process of glioma (i.e., GPR158 expression was highest in the central nervous system (CNS) and oligodendrogliomas, lower in IDH mutant astrocytomas and lowest in the most malignant form of glioma and IDH wild-type glioblastoma) [17].