Abstract: | Mice infected at 2 days of age with a virus that induces reticulum cell sarcoma and myeloerythroleukemia were treated with erythropoietin-containing serum obtained from rabbits that had been treated with acetylphenylhydrazine. A marked inhibition of tumor induction occurred, particularly in females, when treatment was begun early. Delayed treatment resulted in instances of regression of overt neoplasia. |