transfection of the activated ras oncogene ( ha-ras ) into second passage rat embryo fibroblasts can induce the metastatic phenotype , while cotransfection of ha-ras with the adenovirus type 2 e1a gene ( ad2-e1a ) yields cells which are tumorigenic but nonmetastatic in nude mice .
C0016030
fibroblasts
C0007634
cells