Antitumor effects of RNA isolated from murine tumors and embryos.

We describe the antitumor effects of a certain RNA(s) isolated from murine tumors and embryos. A single i.v. injected of 10 to 30 microgram of this RNA(s) induces necrosis, hemorrhages, and regression of solid tumors in the strain of origin; in pregnant mice it is embryotoxic, causing resorption of the embryos, but has no toxic effect upon the tumor-bearing or pregnant host. Its action is highly specific, and its presence in both tumors and embryos suggests that it may result from reexpression of embryonic genes in tumor cells.