The multistep genetic alterations thought to involve both oncogenes and tumor suppressor genes that are causally related to melanocytic transformation remain largely undetermined (1 ). Mapping of alterations to chromosome 6 indicates that multiple genetic loci on 6q contribute causally to the development and progression of malignant melanoma (1 ). This notion is also supported by the introduction of chromosome 6 in malignant melanoma cell lines suppressing either their tumorigenicity (2 ) or metastasis (3 ,4 ). However, the suppressor genes involved have yet to be identified.