In 2000, Yamauchi et al. identified the gene, carbohydrate sulfotransferase 11 (CHST11), encoding chondroitin 4-O-sulfotransferase-1 (C4ST-1), which catalyzes the transfer of a sulfate group from PAPS to the C-4 hydroxy group of GalNAc residues in the repeating disaccharide region of chondroitin, [GlcUA-GalNAc]n (Figure 2), based on the protein sequence of purified C4ST from culture medium of rat chondrosarcoma after treatment with trypsin [121]. This evidence concerns the gene CHST11 and chondrosarcoma.