Study of oncogenic potentialities of human melanoma: identification of N-ras oncogene after DNA transfer and tumour induction.

The oncogenic potentialities of human melanoma cells derived from two different patients were studied using DNA-mediated gene transfer into NIH 3T3 cells followed by tumor induction into athymic nude nice. 64% of the mice injected subcutaneously with selected cells which had been co-transfected with human melanoma DNA and the selective marker NeoR developed tumors within 3-4 weeks, while up to 100% of those injected with cells transfected three days before with melanoma DNA developed tumors within 4-6 weeks. Southern blots analysis of the tumors indicated that almost all of them contained human sequences. Hybridization with different oncogene probes showed the presence of an human Eco RI N-ras-hybridizing fragment in the primary and secondary derived tumors, indicating that a transforming N-ras oncogene in human melanoma had been transferred to recipient cells and that transformed cells induced tumors in nude mice.