CDA and acute myeloid leukemia: (iv) Fourth, adding THU, to inhibit the catabolic enzyme CDA that severely limits decitabine and 5-azacytidine tissue-distribution and half-lives, and that is rapidly upregulated by decitabine (and to a lesser extent 5-azacytidine) in vitro and in vivo, also extended decitabine or 5-azacytidine anti-AML efficacy in vivo.