FUT4 and central nervous system cancer: CD133-CD15- GL261 and primary glioma cells were then cultured in 1% O2 for 72 h, and the results revealed that these cells highly expressed CD133 and CD15 (Fig 1E and Supplementary Figure S1B), and cells cultured in 1% O2 for 24, 48 or 72 h highly expressed CD133 and CD15 in a time-dependent manner under hypoxic conditions (Fig 1F).