In experimental models of adult T-ALL and AML it has been possible to pinpoint CD44 as a direct transcriptional target of Notch signalling, while other observations have implicated the proteoglycan as an inducer of the formation, persistence and progression of pre-leukemic and leukemic cancer stem cells [80, 83, 85, 86]. This evidence concerns the gene CD44 and acute myeloid leukemia.