Background: Ocular melanoma is easily treated by the removal of the eye or through plaque radiotherapy. However, after removal or control of the primary tumor, patients can develop fatal liver metastases up to 20 years later. It has been reported that difficulties in imaging single cells and the propensity for tumor cells to replicate rapidly in animal models account for the deficit of single-cell tumor dormancy models.
Methods: In this paper, we performed two animal experiments using green fluorescent-labeled uveal melanoma cells in nude mice. Cells were injected via tail-vein and the experiments ran 20 and 42 days, respectively. Labeled cells were imaged in vivo via skin-flap and epifluorescent microscopy.
Results: The first experiment exemplified the feasibility of a single-cell tumor dormancy model; cells were present in multiple organs post-injection, but persisted solely in the liver for the duration of the experiment. The second experiment, demonstrating the presence and viability of these single, metastatic seeds 6 weeks after injection.
Conclusion: Due to the inherent difficulties in establishing single-celled tumor dormancy models, few exist. In this paper, we have successfully developed a single-cell dormancy model of uveal melanoma, a disease that, in patients, epitomizes tumor dormancy. This model has the potential to reveal the mechanisms behind dormancy, identify patients at high risk for metastatic development, and develop new serum biomarkers for micrometastasis detection.