GFAP and astroblastoma: GFAP immunoreactivity was identified in the cytoplasm and fibrillary processes of tumors with EPN-like, astroblastoma-like features (Figs. 1g, 2g), whereas no immunopositivity or only a focal expression was detected in tumors with sarcoma-like and PXA-like features (Figs. 3h, 4h).