The initial leukemic CICs that arise after conditional PTEN deletion by themselves are not able to induce leukemia upon transfer into severe combined immunodeficiency (SCID)-recipient mice, but if the leukemic CICs were derived from the PTEN-conditional mice that had developed leukemia, they were able to transfer leukemia to the SCID-recipient mice, which could be prevented by rapamycin treatment [204]. This evidence concerns the gene PTEN and leukemia.