IDH1 and astrocytoma (excluding glioblastoma): When IDH mutant tumors were further divided into 1p19q non-codeleted (astrocytomas) and codeleted (oligodendrogliomas) tumors, GPR133 expression was equivalent within the tumor core (Figure 4Bi), but elevated in the infiltrative edge of non-codeleted specimens (Figure 4Bii).