SLC2A1 and neoplasm: Interestingly, we also observed a decrease in the level of GLUT-1 mRNA even under hypoxic conditions, demonstrating that FIH-1 regulates HIF activity in U87 cells even in hypoxia (Figure 1B), which suggests that hypoxia is not the sole factor for inducing HIF-regulated genes in GBM [6] and FIH-1 involved (mediated) HIF activity regulation may also play role during GBM tumor progression in certain advanced cases.