GFAP and neoplasm: In all cases of differentiation (oligodendrocytic, neuronal and astrocytic) receptor activation in the tumor cell line caused either an increase in the expression of markers representing a less differentiated state (i.e. NCam1, βIII-Tubulin and GFAP) or a decrease or no change in markers representing a more differentiated state (i.e. S100β, PDGFRα and NeuN).