GFAP and glioblastoma: Regarding the diagnosis of GBM-PNC, Arie Perry et al proposed that only gliomas with compelling primitive neuronal cell characteristics, both morphologically and immunohistochemically, should be diagnosed as GBM-PNC.[4] Histopathologically, GBM-PNC consists of 2 components: one is the classic astrocytic tumor area of GBM, which expresses GFAP and Vimentin but does not express SYN; the other is a clearly defined nodular primitive cell area, which exhibits neuronal differentiation (e.g., Homer Wright rosettes).