CHSY1 and central nervous system cancer: Intriguingly, under our staining conditions, no obvious CHSY1 signal was observed in the normal brain tissue (n = 5, Fig. 1d), whereas 85% of grade IV GBM tissues expressed high levels (+2 and +3) of CHSY1, which is significantly higher than that in low-grade glioma and normal brain tissue (Fig. 1e and Supplementary Table S1).