An in vitro screening method for antitumor and/or antitumorigenic substances involving the transformation of chick embryo fibroblasts infected with Rous sarcoma virus.

An efficient in vitro screening method for antitumor and/or antitumorigenic substances was established. The method is based on determining inhibitory effect of a compound on an RSV-induced tumorigenic process and the growth of the established tumor cells in a single assay system in the presence of normal cells. These effects were determined by inhibition of focus formation in a culture of chick embryo fibroblasts, while the nonspecific cytotoxic effect was determined by inhibition of the protein content of the same culture. The efficiency of this method in screening drugs was confirmed by testing various clinical and preclinical compounds.