The significant down-regulation of core and ancillary clock genes seen in AML patients at the end of treatment gives rise to the possibility of these genes being used as potential biomarkers to assess efficacy in the treatment of AML and the up-regulation of Cry2 could be used as a potential biomarker to assess relapse status in AML before other diagnostic tests are carried out to confirm that the disease has relapsed in patients. This evidence concerns the gene CLOCK and acute myeloid leukemia.