Figure 5

Characteristics of the metastatic potential of Luc-expressing 4T1 cells in the orthotopic breast cancer model evaluated by BLI and confirmed by MRI. Small metastases of 4T1luc2D6 cells in the lungs and soft tissues one week after removal of the primary focus (week 4 after the implantation of 4T1lucD6 cells) visualized by micro-CT, 3D BLI (A,B), and verified by histochemistry (C,D,E,F). Metastasis as a single source of luminescence are detectable in the lung and neck (A), and in the lung and muscle tissues of the lower right foreleg (B), panels I, II, III demonstrate microCT xy-, yz-, and zx- projections respectively, and panel IV, 3D reconstruction of microCT and BLI (A,B); Histological verification of the multiple 200–500 μm metastasis in lungs (C,D), and muscle tissues (E,F); Metastases in muscle tissue, 300 × 600 μm in size, detected by bioluminescence imaging (E). Hematoxylin-eosin staining of sections of paraffin-block preparations of the lung metastases (C,D) and metastases in muscle tissue (E,F) demonstrated hypercellular foci consisting of the polymorphic cells characteristic of the high-grade carcinomas. Magnification 50× (C,E) and 200× (D,F); scale bar 50 μm.