Fibronectin from human germ-cell tumors resembles amniotic fluid fibronectin

Three human germ-cell tumors established as xenografts in immunosuppressed mice were shown to produce fibronectin. Immunoperoxidase tissue staining with a specific antiserum revealed human fibronectin in some tumor cells. The cyst fluid which accumulated in the tumors contained human fibronectin as shown by a species-specific radioimmunoassay. Human fibronectin was isolated from two of the tumor fluids and compared to previously characterized fibronectins. Sodium dodecyl sulfate/polyacrylamide gel electrophoresis and gel electrofocusing showed that the germ-cell fibronectins resembled amniotic fluid fibronectin with regard to subunit molecular weight and isoelectric point. The distinct features of the amniotic fluid and germ-cell tumor fibronectin suggest that such fibronectins may provide new oncodevelopmental markers.