[Electron microscopic detection of the proteoglycan component of the extracellular matrix in osteogenic sarcomas]

Electron-microscopic studies in which Alcian blue was used to demonstrate proteoglycans (PG) revealed a predominance of largely undifferentiated tumor cells in two of the osteosarcomas examined; the extracellular matrix of these tumors had few PG-containing structures. Other osteosarcomas, where cells of the osteoblastic type prevailed, were found to possess PG granules on the cell surface and a rough PG network in the pericellular space. In a parosteal osteosarcoma, which contained strongly elongated fibroblast-like cells, PG formed a fine mesh both in the pericellular space and throughout the extracellular matrix. A correlation therefore exists between the ultrastructure of the PG component in the extracellular matrix of osteogenic sarcomas and the degree and direction of tumor cell differentiation.