Since radial glia are considered progenitors in normal CNS development and have been implicated as a possible cell of origin in supratentorial ZFTA tumors [10], the finding of GFAP-positive fibrillary processes in ependymoma may reflect either astroglial, subependymal, tanycytic, or radial glial-like states. Here, GFAP is linked to ependymoma.