Uniform lineage of oligodendrogliomas.

Experimental observations provide evidence that galactocerebroside-containing (GC+) oligodendrocytes and glial fibrillary acidic protein-containing (GFAP+) type 2 astrocytes are derived from A2B5+ progenitor cells. Because the cytomorphologic features of oligodendrogliomas resemble those of non-neoplastic oligodendrocytes, it was speculated that neoplastic oligodendroglial cells also have A2B5+ lineage. This hypothesis was investigated by immunostaining histopathologic sections with monoclonal antibodies to GC, A2B5, and GFAP. In 28 tumors, ubiquitous immunolabeling of neoplastic cells with anti-GC and anti-A2B5 was observed. In addition, GFAP+/A2B5+ astrocytes were present in most mixed glial tumors. The findings suggest that oligodendrogliomas, whether or not they contain foci of astrocytoma, are uniformly derived from A2B5+ progenitor cells.