Fig. 4

Ex vivo analysis of U87-NIS tumors. a, c NIS (green) and CD31 (red, labeling tumor vascularization) immunofluorescence staining of cryosections of U87-NIS flank and brain tumors. Nuclei are stained in blue. NIS protein expression is shown at the cellular membrane (white arrows) of the tumor cells.  Increased vascularization of brain tumors is detected as compared to normal brain tissue as well as in contrast to the s.c. model. Section thickness 5 µm (s.c. tumors) and 10 µm (brain section). b, d H&E of s.c. U87-NIS xenograft tumor and horizontal section of the brain for visualization of the tumor mass. The area of implantation in the right caudate putamen of orthotopic xenografts is shown, the tumor is circled in yellow