Human
gliomas including
astrocytomas and
oligodendrogliomas are defined as being composed of neoplastic astrocytes and oligodendrocytes respectively. Here, on the basis of in vitro functional assays, we show that
gliomas contain a mixture of glial progenitor cells and their progeny. We have set up explant cultures from
pilocytic astrocytomas,
glioblastomas and
oligodendrogliomas and studied
antigens that characterize glial lineage, from the precursor cells (glial restricted precursors and oligodendrocyte-type2-astrocyte/oligodendrocyte precursor cells expressing the A2B5
ganglioside) to the differentiated cells (oligodendrocyte and type-1 and type-2 astrocytes). All tumoral explants contain A2B5+ cells and can generate migrating cells with distinctive functional properties according to
glioma subtypes. In
pilocytic astrocytomas, very few migrating cells are dividing and can differentiate in type-2 astrocytes or towards the oligodendrocyte lineage. In
glioblastomas, most migrating cells are dividing, express A2B5 or
glial fibrillary acid protein (GFAP) and can generate oligodendrocytes and type-1 and type-2 astrocytes in appropriate medium.
Oligodendroglioma explants are made by actively dividing glial precursor cells expressing A2B5 or
PSA-NCAM. Only few cells can migrate and differentiation towards oligodendrocyte lineage does not occur. Isolated A2B5+ cells from both
glioblastomas and
oligodendrogliomas showed similar genetic alterations as the whole tumour. Therefore,
pilocytic astrocytomas contain slowly dividing oligodendrocyte-type2-astrocyte/oligodendrocyte precursor cells in keeping with their benign behaviour whereas both
glioblastomas and
oligodendrogliomas contain neoplastic glial restricted precursor cells. In
oligodendrogliomas, these cells are trapped in undifferentiated and proliferating state. The precursor cells properties present in
gliomas give new insight into their histogenesis and open up new avenues for research in the field of gliomagenesis.