Daoy medulloblastoma cells that express CD133 are radioresistant relative to CD133- cells, and the CD133+ sector is enlarged by hypoxia.

Purpose: Primary medulloblastoma and glioblastoma multiforme tumor cells that express the surface marker CD133 are believed to be enriched for brain tumor stem cells because of their unique ability to initiate or reconstitute tumors in immunodeficient mice. This study sought to characterize the radiobiological properties and marker expression changes of CD133+ vs. CD133- cells of an established medulloblastoma cell line.