A human uveal melanoma cell line (92-1) was established from a primary uveal melanoma, and has now been maintained in culture for over 2 1/2 years. Light microscopy of the cultured cells demonstrated extremely pleiomorphic cells with large prominent nucleoli. Cell proliferation was determined with a non-radioactive propidium-iodide assay and indicated an in vitro doubling time of approximately 58 hr. Furthermore, the cell line was characterized by cytogenetic analysis, electron microscopy, immunocytochemistry and Northern blotting for HLA and c-myc-mRNA analysis. Cytogenetic analysis revealed numerical abnormalities of chromosome 8 and structural abnormalities of chromosome 6. By electron microscopy, different stages of melanosome development were observed. Immunocytochemical analysis demonstrated expression of the melanoma-associated antigen gp 100. Expression analysis of HLA antigens revealed a very low level of, in particular, the HLA-B locus products, which could be induced by interferon-alpha or -gamma treatment. Likewise, Northern-blot experiments revealed decreased levels of HLA-B mRNA as compared with HLA-A. In addition, high levels of c-myc expression were observed. The phenotypic characteristics of the cultured cells indicate that we have established an uveal melanoma cell line. This now well-characterized uveal melanoma cell line can be used in future studies.