Causal role for an activated N-ras oncogene in the induction of tumorigenicity acquired by a human cell line.

ras oncogenes have been found in approximately 15% of the human tumors analyzed. However, a causal role for these genes in the tumorigenesis of human cells has yet to be shown. Tumorigenic late-passage PA-1 human teratocarcinoma cells (E-PA-1) contain an activated N-ras gene. In this report evidence is presented that nontumorigenic early passage revertant PA-1 cells (E-PA-1) contain only the germ-line protooncogene. Introduction by gene transfer of the activated L-PA-1 oncogene induces E-PA-1 cells to form tumors, suggesting that the activated N-ras oncogene has a causal role in the tumorigenesis of these cells.