Radial glia cells are candidate stem cells of ependymoma.

Tumors of the same histologic type often comprise clinically and molecularly distinct subgroups; however, the etiology of these subgroups is unknown. Here, we report that histologically identical, but genetically distinct, ependymomas exhibit patterns of gene expression that recapitulate those of radial glia cells in the corresponding region of the central nervous system. Cancer stem cells isolated from ependymomas displayed a radial glia phenotype and formed tumors when orthotopically transplanted in mice. These findings identify restricted populations of radial glia cells as candidate stem cells of the different subgroups of ependymoma, and they support a general hypothesis that subgroups of the same histologic tumor type are generated by different populations of progenitor cells in the tissues of origin.