Up-regulation of PER3 Expression Is Correlated with Better Clinical Outcome in Acute Leukemia.

Background: Altered expression of circadian clock genes has been linked to various types of cancer. This study aimed to investigate whether these genes are also altered in acute myeloid leukemia (AML) and acute lymphoid leukemia (ALL). Materials and Methods: The expression profiles of nine circadian clock genes of peripheral blood (PB) leukocytes from patients with newly-diagnosed AML (n=41), ALL (n=23) and healthy individuals (n=51) were investigated. Results: In AML, the expression of period 1 (PER1), period 2 (PER2), period 3 (PER3), cryptochrome 1 (CRY1), cryptochrome 2 (CRY2), brain and muscle aryl hydrocarbon receptor nuclear translocator (ARNT)-like 1 (BMAL1), and timeless (TIM) was significantly down-regulated, while that of CK1 epsilon was significantly up-regulated. In ALL, the expression of PER3 and CRY1 was significantly down-regulated, whereas those of CK1 epsilon and TIM were significantly up-regulated. Recovery of PER3 expression was observed in both patients with AML and those with ALL who achieved remission but not in patients who relapsed after treatment. Conclusion: Circadian clock genes are altered in patients with acute leukemia and up-regulation of PER3 is correlated with a better clinical outcome.