Expression of neuronal markers in oligodendrogliomas: an immunohistochemical study

Abstract

The oligodendroglioma has been considered to be a tumour showing oligodendrocyte differentiation, but studies of the expression of oligodendrocyte markers have not conclusively demonstrated this and the pattern of differentiation of this tumour remains uncertain. Recent studies have suggested that some oligodendrogliomas may show neuronal differentiation. The aim of this study was to determine whether there was evidence of neuronal differentiation in a series of oligodendrogliomas, and, if so, to determine whether this identified a biologically or clinically distinct group. Immunohistochemistry was carried out on paraffin sections using antibodies to synaptophysin, phosphorylated and non-phosphorylated neurofilament proteins. An archival series of 32 oligodendrogliomas had been previously characterized for histological features, histological grade, Ki-67 labelling index, apoptosis index and prognosis. Six per cent of tumours showed expression of synaptophysin. Thirty-one per cent of cases showed expression of neurofilament proteins with an antibody to non-phosphorylated epitopes, but no cases were positive with antibodies to phosphorylated neurofilament epitopes. Tumours showing expression of neuronal markers did not show a difference in the distribution of histological grade or GFAP expression from those which did not express these markers, and there was no difference in labelling indices or prognosis between the two groups. In conclusion, a subset of oligodendrogliomas showed expression of neuronal lineage markers; this is discussed in relation to histogenesis and differential diagnosis. The expression of such markers did not identify a biologically or clinically distinct subgroup.

α-Synuclein is expressed in a variety of brain tumors showing neuronal differentiation

“…It has recently been reported that oligodendroglioma also expressed synaptophysin and showed a similar histological appearance to that of neuronal tumors [23,30,33]. In this study oligodendrogliomas showed diffuse, positive immunoreactivity for synaptophysin (83%); however, α-synuclein-immunoreactivity was only detected in a single case (17%), which could be due to the involvement of the normal cerebral cortex.…”

Spinal cord glioneuronal tumor with neuropil-like islands with 1p/19q deletion in an adult with low-grade cerebral oligodendroglioma

“…Oligodendrocytes and particular neuronal subpopulations have also been shown to arise from a common developmental precursor by means of OLIG expression [22]. However, as noted by Barbashina et al [8], this discussion is complicated by the observation that conventional oligodendrogliomas can express neuronal markers, such as synaptophysin [23].…”

Persistence of a small subpopulation of cancer stem-like cells in the C6 glioma cell line

“…Many cancers, like normal organs, seem to be maintained by a hierarchical organization that includes slowly dividing stem cells, rapidly dividing transit amplifying cells (precursor cells), and differentiated cells (2)(3)(4)(5)(6). Malignant gliomas, for example, often contain both undifferentiated and differentiated cells and sometimes contain cells that express neuronal markers as well as cells that express glial markers, suggesting that they may contain multipotent neural stem cell (NSC)-like cells (7)(8)(9). Such mixed gliomas may develop from NSCs or from more restricted glial lineage cells that acquire multipotential stem-cell-like properties by mutation (10,11).…”