Metastatic failure of B16FO melanoma cells inoculated in different and non-typical organs of athymic male nude mice and female C57BL6 mice

Abstract

Background: Cancer is the second leading cause of death in the world. Metastasis is the process by which tumor cells leave the primary site and form colonies in different locations. The risk of metastasis makes cancer difficult to treat and accounts for a 90 percent mortality rate. A major problem in studying metastasis has been a lack of suitable models that faithfully represent the metastatic process as it occurs in vivo. Purpose: In order to mimic the potential of tumor metastasis in humans, we used a highly aggressive B16FO murine melanoma cell line, and showed that B16FO melanoma can metastasize to various sites. In the current study we investigated whether B16FO cells inoculated in the non-typical organs in male nude mice and female C57BL6 mice have the potential to metastasize to distant organs. As such, we injected B16FO cells in prostate, seminal vesicles and the pancreas of male nude mice and in mammary pads of female C57BL6 mice. The animals were kept on recommended diet and sacrificed after three weeks. Results: We observed that while the animals did develop tumors at the sites of inoculation, the B16FO cells did not induce metastasis in any of the vital organs. It is possible that although B16FO are very aggressive cells, the three weeks were not enough for metastasis to develop. Otherwise it could be the tumor dormancy period. Conclusion: We conclude that out of the four inoculation sites we tested in this series of experiments such as the prostate, seminal vesicles, the pancreas and mammary pads of nude or C57BL6 mice are not the best route for future investigation of melanoma metastasis.