GFAP and myeloid sarcoma: Currently, the MS prognostic biomarkers that have been investigated the most include IgG oligoclonal bands [28], neurofilament light chain (NfL) [29,30,31], glial fibrillary acidic protein (GFAP) [30,31], chitinase 3-like protein 1 (CHI3L1) in CSF [32], and serum [33,34].