CLOCK and leukemia: Taken together, these data support the notion that SIRT1 has a role in regulating the circadian clock in leukemia and that the targeting of SIRT1 and therefore the molecular clock using chronopharmacological agents such as EX527 could prove to be a novel and effective therapeutic strategy for improving dysfunctional circadian rhythms in leukemia and thus for both improving the effectiveness of existing chemotherapeutic drugs and reducing drug-associated toxicity.