Ocular metastasis of in vivo and in vitro derived syngeneic murine melanoma.

We examine ocular metastasis of syngeneic murine melanoma in C57Bl/6J mice and compare the metastatic capability of B16F10 tumor cells maintained in vivo with those maintained in culture. We demonstrate that as long as the tumor cells are derived from an in vivo source, intraocular tumor readily metastasizes to the lungs. When in vivo derived tumor is introduced as an intracameral (ic) cell suspension, or as a solid fragment implanted on the iris, 100% of the animals die with extensive pulmonary metastasis 5-6 weeks later. In contrast, when B16F10 cells are passaged five times in culture and inoculated ic, a marked decrease in the frequency and extent of metastasis, and an increase in survival is seen. These studies demonstrate an alteration in the ability of cultured B16F10 cells to metastasize from the eye. When metastasis of in vivo derived tumor from the eye was compared with metastasis from an extraocular location, the extent and frequency of pulmonary metastasis and survival of hosts was the same. The effect of enucleation on the metastasis of B16F10 from the eye has only previously been examined using cultured cells. In this paper, we demonstrate that the efficacy of enucleation depends upon whether B16F10 melanoma cells have been passaged in vivo or in vitro.