Myelin-associated proteins are potential diagnostic markers in patients with primary brain tumour

Taking into account the possibility of myelin-associated proteins having a role in brain tumour development, the study aimed to evaluate the diagnostic usefulness of myelin-associated proteins (Nogo-A, MAG, OMgp) released into extracellular space in patients with brain tumours. Protein concentration in primary brain tumour (n = 49) and non-tumoural subjects (n = 24) was measured in cerebrospinal fluid (CSF) and serum by means of ELISA. Immunohistochemistry for IDH1-R132H was done on 5-μm thick formalin-fixed, paraffin-embedded tumour sections with the use of an antibody specific for the mutant IDH1-R132H protein. The receiver operator characteristic curve analysis showed that CSF Nogo-A and serum MAG were useful in differentiating patients with primary brain tumour from non-tumoural individuals. This was also true in the case of the separate analysis of the astrocytic tumour versus non-tumoural groups and the meningeal tumour versus non-tumoural groups. Neither Nogo-A nor MAG or OMgp concentrations were significantly different, in serum or CSF, between IDH1 wild-type astrocytic brain tumour patients compared to IDH1 mutant patients. Our results indicated the potential usefulness of CSF Nogo-A and serum MAG evaluation as circulating biomarkers of primary brain tumours. Because blood is relatively easy to obtain, future research should be conducted to explicitly indicate the value of serum MAG concentration evaluation as a brain tumour biomarker. Key messages Myelin-associated proteins may be circulating brain tumour biomarkers. Nogo-A and MAG proteins seem to be the most useful in brain tumour diagnosis. Decreased CSF Nogo-A concentration is an adverse prognostic factor for patients' survival.