Accordingly, Yang et al. [91] demonstrated that patients afflicted with either AML or ALL only had elevated levels of PER1 and PER3 at the end of their treatment, respectively, indicating that this high expression of the Period genes could also play an active role in tumor suppression in leukemia, as described in other cancer types [99,100,101]. This evidence concerns the gene PER1 and acute lymphoblastic leukemia.