Expression of MAGE genes in ocular melanoma cell lines.

The pathobiology of melanomas that develop within the eye is distinct from melanomas that develop within the subcutaneous tissues of the skin. This may be related to the unique structural and functional differences between normal melanocytes present within the uveal tract of the eye and the epidermal layers of the skin. The purpose of the present study was to determine whether normal pigmented cells within the eye (melanocytes and retinal pigment epithelial cells) and cultured cells derived from malignant ocular melanomas express the MAGE genes that encode tumor antigens that are recognized by specific CD8+ cytotoxic T lymphocytes. In the present series of experiments, we examined MAGE expression in cultured ocular melanoma cells obtained from a group of 17 ocular melanoma patients. Normal ocular melanocytes and retinal pigment epithelial cells were recovered and cultured from eyes enucleated for trauma. MAGE gene expression was determined using reverse transcription-polymerase chain reaction specific for either MAGE-1, -2, or -3. Our results demonstrate that MAGE-1, MAGE-2, and MAGE-3 genes are transcribed in primary ocular melanoma cell lines and are detected in cells recovered from 41, 53, and 53% of the patients examined, respectively. Normal choroidal melanocytes and retinal pigment epithelial cells did not express MAGE genes. We conclude that cultured ocular melanoma cell lines express MAGE-1, MAGE-2, and MAGE-3 genes.