The CGs BMAL1, PER1, PER2, PER3, NAPS2, TIM, CRY1, CRY2, CKIε, CLOCK, REV-Erα, PPARα, and SHARP1 were the more frequent genes described in the pointed studies; their function was correlated with their expression levels in leukemia patients. The gene discussed is CRY2; the disease is leukemia.