Production of the metastatic phenotype with DNA from metastatic cells but not with oncogenic DNA

Although the tumorigenic phenotype can be transferred by transfecting DNA from a variety of human tumours into 3T3 mouse fibroblasts, the ability to transfer the metastatic phenotype in a similar manner in syngeneic animals is largely unknown. We now report that transfection of a rat mammary epithelial cell line Rama 37, which produces nonmetastasizing adenomatous tumours in syngeneic rats, with DNA from a metastasizing rat mammary cell line, Rama 800, yields some transfectants with reproducible metastatic capabilities. Nonspecific DNA or the oncogenes <sub>EJ-ras-1,</sub> or Polyoma Large T Antigen fail in this respect, although their transfectants often possess increased tumorigenic potential