Amplification of activated c-Ha-ras-1 in human melanoma.

Two alleles of c-Ha-ras-1 in a human melanoma could be distinguished by restriction fragment length polymorphism, and one of them was demonstrated to be amplified 10-20 times by hybridization to a specific probe. Molecular cloning and nucleotide sequence analysis revealed that the amplified allele contained the activated c-Ha-ras-1. In the ras family, amplification of c-Ki-ras-2 and c-Ha-ras-1 has been demonstrated in several human tumors. However, the present result provides the first direct evidence that gene amplification occurs in the activated allele.