Rana et al. [30] investigated the expression of four circadian clock genes (PER1, PER2, BMAL1, and CLOCK) and three clock-controlled cell cycle genes (Wee1, Cyclin D1, and Myc) in 37 patients with chronic lymphocytic leukemia (CLL) and an equal number of healthy controls. The gene discussed is PER2; the disease is B-cell chronic lymphocytic leukemia.