A-E. Visualization of lymphatic vessels in a double transgenic mouse model. SV40-lacZ mice obtained by crossing κB-lacZ mice with UPKII/SV40 maintain the capacity of the parent mice in developing bladder carcinoma in situ (CIS) and labeling of bladder lymphatic vessels. A represents X-Gal staining of bladder whole mounts isolated from SV40-lacZ mice, indicating a rich network of lymphatic vessels in the bladder adventitia. Cross-sections of the urinary bladder illustrated in A were left unstained (B) or counter stained with H&E (C-D). Figure C is a representative of bladder adventitia and D is a high magnification of lymphatic vessels present in the detrusor smooth muscle. Arrows (B, C, and D) indicate the presence of β-galactosidase-positive lymphatic endothelial cells. E is a representative whole mount of bladders isolated from SV40-lacZ mice subsequently stained with X-gal to reveal β-galactosidase-positive cells (blue) and LYVE-1 IHC to reveal lymphatic endothelial cells (brown). Note the complete overlap of labels confirming constitutive NF-κB activity in lymphatic vessels.