SULF2 and head and neck squamous cell carcinoma: To further evaluate the composition of heparan sulfate chains, we analyzed composition of HS disaccharides in FFPE sections of 10 SULF2-positive (SULF2+ve) and 11 SULF2-negative (SULF2-ve) tumors from 21 HNSCC patients by LC-MS/MS (16) (Figure 4A).