RTN4 and neurosarcoidosis: An inflammatory state, which accompanies neoplasms, is rather not the source of CSF Nogo-A in patients with primary brain tumors, as Jurewicz et al. [13] revealed negative Nogo-A Western-blot results in the cerebrospinal fluid of patients with meningo-encephalomyelitis, Creuzfeldt-Jakob disease, systemic lupus erythematosus, neurosarcoidosis, as well as other inflammatory diseases of the central nervous system.