S100A9 and glioblastoma: Differently, 12 precursor proteins, namely, PRR27, CRISP3, CPSF6, GLUL, HBB, SCAF4, GAPDH, TMSB4X, HBA1, S100A9, CSTB, and SPRR3, distinguished GBM saliva from CTRL, being commonly identified in both ND and R GBM T0 pre-surgery saliva.