A novel application of dorsal window chambers: repetitive imaging of tumor-associated lymphatics.

The purpose of this study was to establish a lymphangiography assay allowing repetitive imaging of tumor-associated lymphatics, and to investigate potential associations between tumor-induced changes in pre-existing lymphatics and tumor angiogenesis. A-07-GFP human melanoma xenografts grown in dorsal window chambers were used as preclinical tumor model. Lymphatics were visualized after multiple intradermal injections of 155 kDa tetramethylrhodamine isothiocyanate dextran outside the window chambers, and tumor vasculature was assessed from high-resolution transillumination images. Lymphangiography was performed thrice in window chambers with or without A-07-GFP tumors, with 3-4 days between repetitions. The lymphangiography assay was highly reproducible. A-07-GFP tumors induced dilation of pre-existing lymphatics after the onset of tumor angiogenesis, and the dilation was correlated with tumor size.