Visualization of luciferase expression pattern of AdCXCR4Luc and AdCMVLuc in normal breast tissue slices versus breast cancer tissue slices. The upper panels show the tissue morphology as revealed by hematoxylin-and-eosin staining of thin sections of (a) normal breast tissue slices and (b) breast tissue slices. Representative indirect immunfluorescent detection of luciferase expression is shown in the lower panels for (a) human normal breast tissue slices and (b) breast cancer tissue slices infected with AdCXCR4Luc and AdCMVLuc. AdCMVLuc infected (a) normal breast tissue slices (lower left panel) and (b) breast cancer tissue slices (lower left panel) show immunofluorescent detection of the luciferase protein (green fluorescence), whereas (a) AdCXCR4 infected normal breast tissue slices (lower right panel) do not display luciferase activity. In contrast, (b) AdCXCR4 infected breast cancer tissue slices reveal luciferase activity (lower right panel). DAPI (4'6-diamidino-2-phenylindole 2HCL) staining (blue) indicates nuclei. Magnification ×200.