NES and central nervous system cancer: To avoid this possibility, we detected the rate of newly formed neurospheres by a single CD133−/CD15−/NESTIN− glioma cell; the results indicated that more than 95% glioma cells (d21 neurospheres/d3 viable cells) formed neurospheres with an increased expression of CD133, CD15 and NESTIN after hypoxia exposure for 21 d; however, the cells cultured in normoxia or hyperoxia maintained a single cell and eventually died.