Therefore, to investigate the relative effects of tumor suppressor loss on progeny and recruited cells, we induced gliomas in Ntv-a mice with germline deletions of Ink4a, Arf and/or Pten, the latter achieved by Cre-mediated recombination of the floxed Pten alleles by RCAS-Cre [36], [37]. The gene discussed is PTEN; the disease is neoplasm.