SLC7A11 and neoplasm: These results indicate that severe hypoxia at 1% O2 increases CD44, resulting in promotion of higher migration and invasion of GSCs, whereas moderate hypoxia at 5% O2 increases xCT expression, resulting in accumulation of extracellular Glu, leading to promotion of postoperative epileptogenicity in GBM as well as tumor proliferation (Figure 6).