HAS1 and malignant glioma: HA-related synthases (HAS1, HAS2, and HAS3) and the receptor CD44 play important roles in the synthesis and biological function of HA, therefore, bioinformatics analysis was performed to analyze the expression of HA synthases and CD44, the results indicated that HAS1 expression was negatively correlated with the DFS time of patients with high-grade glioma (Supplementary Fig. 1A); however, the correlation was not significant for patients with LGG.