Similarly, a mouse model of Tyr-H-RASV21Gink4a/Arf−/− in a Pten+/+ or Pten+/− background showed that inactivation of one copy of Pten led to earlier onset of melanoma whereas mice without activated Ras in the Pten+/−Ink4aArf−/− background did not give rise to animals with melanoma (Nogueira et al., 2010). The gene discussed is PTEN; the disease is melanoma.