Ki-67 immunostaining in uveal melanoma. The effect of pre-enucleation radiotherapy. The reactivity of 33 choroidal and ciliary body melanomas with monoclonal antibody Ki-67, which recognizes a proliferation associated nuclear antigen, has been assessed and compared with clinicopathologic parameters. In 23 cases, 8 Gy irradiation was given 2 days before enucleation. Nonirradiated melanomas had a significantly higher proliferation rate as defined by staining with monoclonal antibody Ki-67 as compared with irradiated tumors (P = 0.007). Similarly, a strong relationship was found between pre-enucleation irradiation and low mitotic activity (P = 0.001). There was no significant correlation between the presence of Ki-67-positive nuclei and histologic classification, largest tumor diameter, localization of the tumor, age, sex, scleral invasion, pigmentation, and lymphocytic infiltration. The relevance of Ki-67 immunohistochemistry for the assessment of the life prognosis of patients with uveal melanoma has to be studied prospectively. 