HAS1 and central nervous system cancer: Moreover, in view of HAS1, HAS2, and HAS3 expression in glioma, we over-expressed HAS1 and knocked down HAS2 in glioma cell lines, the results demonstrated the over-expression of HAS1 or the silencing of HAS2 did not significantly affect the viability of glioma cells (Supplementary Fig. 1C).