GFAP and astrocytoma (excluding glioblastoma): Increased GFAPδ expression in spinal cord astrocytoma compared to control tissue.Strong positive correlation of GFAPδ with astrocytoma grade.Weaker positive correlation of pan GFAP with astrocytoma grade.Grade I and II: GFAPδ expression in stellate polygonal or round cells.Grade III: GFAPδ expression in round and spindle‐shaped cells.