Fig. 1. PEDF expression increased with increasing tumor differentiation. Tumors displaying different levels of differentiation were stained with an antibody raised to peptides derived from PEDF. (A) Undifferentiated tumor, arrows indicate weakly staining endothelial cells. (B) A neuroblastoma with some diffentiated cells, arrow indicates a mature ganglion cell. (C) A ganglioneuroblastoma, a tumor with many differentiated cells that stained most strongly, arrow indicates Schwann cells. Magnification, 10x (A,C); 20x (B).