Abstract

The binding activities of 6 plant lectins were studied in a total of 6 cases of Ewing's sarcoma of the bone, using the avidin-biotin-peroxidase complex (ABC) method on paraffin embedded material. The lectins used in this study were Ricinus communis agglutinin I (RCA I), Concanavalin A (Con-A), Peanut agglutinin (PNA), Wheat germ agglutinin (WGA), Ulex europeus I (UEA I), and Soybean agglutinin (SBA). However, no specific lectin, which showed consistent binding activity in the majority of Ewing's sarcoma cells was identified, in 5 of 6 cases, intracytoplasmic RCA I binding cells were occasionally observed, at somewhat regular intervals, among the neoplastic cell nests. Con-A stains were also positive in 4 cases, but the numbers of Cona-A binding cell were fewer than that of positive cell with RCA I, With PNA, WGA, UEA I, and SBA virtually no tumor cells were stained. These findings suggest that all Con-A positive cells and a part of RCA I binding cells are probably stromal macrophage-histiocytes, which are incorperated in neoplastic cells. And remaining RCA I positive cells seem to be either a kind of differentiating neoplastic cells or supporting cells having close correlation with the neoplastic cells.

• Keywords: Lectin;Ewing's sarcoma;Bone tumor;