TWIST1 and acute myeloid leukemia: TWIST has also been shown to function as a tumor suppressor in AML via direct regulation and activation of the tumor-suppressor gene p21. Similar to observations made in other leukemias [207,208], this pathway was epigenetically silenced by hypermethylation in 31% of adult AML patients, which provided leukemic cells with a proliferation and survival advantage [209].