Hydroxyurea: suppression of two-stage carcinogensis in mouse skin

Hydroxyurea, a selective cytotoxic agent for cells in DNA synthesis, injected intraperitoneally at 24 and 48 hours after the first painting with 1 percent croton oil, significantly reduced the tumor yield in the two-stage chemical carcinlogenesis in mouse skin. A comparable group of mice receiving hydroxyurea only once at 24 hours had a tumor induction similar to that in controls.