A novel transforming gene in a human malignant melanoma cell line

Cellular transforming genes can be detected in human tumours by DNA-mediated transfection into NIH 3T3 mouse fibroblasts 1,2 . The activated transforming genes have been, in most cases, members of the ras gene family, of which the most frequently found is the c-Ki- ras oncogene 3–7 and least frequently the c-Ha- ras gene 8–10 . An increasing number of studies has identified the presence of activated N- ras (which has no known viral homologue) in human tumour cell lines 11–18 . Furthermore, other transforming genes, distinct from the ras gene family, have been reported in B-and T-cell lymphomas 19,20 . The activation of c-Ha- ras and N- ras has been described in some cell lines derived from cases of human malignant melanoma 21 . Here we describe the presence of transforming activity in the DNA from a human melanoma cell line which shows weak homology with members of the ras oncogene family.