Myelin basic protein as a possible marker for oligodendroglioma.

To search for a marker for oligodendroglioma, immunohistochemical analysis of myelin basic protein (MBP) and glial fibrillary acidic protein (GFAP) were performed on tissues from 38 oligodendrogliomas. MBP was detected in 14 such tumors, positive cells being characterized by having rather rich cytoplasm containing a large nucleus and a prominent nucleolus. They seemed to be relatively poorly differentiated cells corresponding to oligodendroglioma grade II in the WHO classification, and appeared to have some cytological resemblance to immature oligodendrocytes in the newborn brain. Mature grade I tumor cells with a small dark nucleus and a perinuclear halo, and grade III anaplastic cells were MBP-negative. GFAP-positive cells were also found in tumors containing MBP-positive cells. A double immunostain for MBP and GFAP demonstrated that some tumor cells were simultaneously stained with both. Presumably the oligodendroglioma cells that showed such dual immunostaining would intrinsically express a myelin-forming glial phenotype. MBP may be applicable as a marker for oligodendrogliomas.