CHSY1 and glioblastoma: Chondroitin sulfate synthase 1, CS polymerization enzyme, has been significantly upregulated in GBM compared to normal brain tissue, and chondroitin sulfate synthase 1 mediates the increase of 6-O sulfation of CS in human glioma (44), supporting our finding of elevated 6-O CS sulfation in GBM samples.