Hamster Greene melanoma in the rabbit eye: immunosuppressive treatment to improve this tumor model.

BACKGROUND

The hamster Greene melanoma (HGM) implanted in the anterior chamber of the rabbit eye has been used to study experimental therapies for human uveal melanoma. However, the occurrence of spontaneous necrosis limits the value of this model for long-term evaluation of experimental treatments. In the present study we tested the hypothesis that an immune response is the cause of this necrosis and that prevention of the immune response can prolong the experimentation time

METHODS

HGM was implanted in the anterior chamber of control, presensitized and immunosuppressed rabbits. The effects of sensitization and immunosuppression were assessed by clinical and histological observation

RESULTS

Sensitization led to a significant slowing down of tumor growth, but not to a difference in necrosis. Immunosuppressive treatment with cyclosporin A improved the success rate of implantation and decreased the amount of necrosis in the tumor

CONCLUSION

The immune response plays a role in the occurrence of necrosis. However, although immunosuppressive treatment with cyclosporin A decreased the amount of necrosis, significant necrosis still occurred, suggesting that other factors like angiogenesis play a part as well and still limit the usefulness of this model in the long-term evaluation of experimental therapies.