Gene expression changes of cell cycle inhibitors ATM, p53, p21, p27, and Rb and cell cycle activator CCNE2 (cyclin E2) were analysed in NB4, HL60, and APL patient cells after 6 and 72 hours of treatment with 3-Deazaneplanocin A and Belinostat in different combinations with Retinoic acid and Idarubicin (Figure 2(b)). This evidence concerns the gene TP53 and acute promyelocytic leukemia.