NEFL and myeloid sarcoma: Notably, an increase of neurofilament light chain in serum has been considered as a potential pre-symptomatic biomarker of neurodegeneration in MS (Bjornevik et al. 2019; Varhaug et al. 2019); however, comparable changes also appear in other neurodegenerative disorders as well as in cases of neurotrauma raising questions as to the selectivity of this as a biomarker for MS, unless specific proteoforms are found to be altered in the different conditions (Sen et al. 2021).