Lectins: reliable differentiation markers in human oligodendrogliomas.

Ninety tumours classified as well-differentiated oligodendrogliomas (43 cases) and anaplastic oligodendrogliomas (47 cases) were studied with glial fibrillary acidic protein (GFAP) and bound with different lectins including: peanut agglutinin (PNA), concanavalin A (Con A), wheat germ agglutinin (WGA) and Ricinus communis agglutinin (RCA-1). PNA has shown high affinity to cellular membranes of well-differentiated oligodendrogliomas. The affinity decreases with the cellular differentiation to astrocytic lines and is lost in anaplastic oligodendrogliomas. Con A labelling is restricted to anaplastic oligodendroglioma cells and to reactive astrocytes showing a predominant somatic (cytoplasmatic) pattern of staining. Our findings showed that a combined search with GFAP and lectins may allow an accurate grading of oligodendrogliomas.