In many previous studies HDAC inhibitors as SB have shown an influence on cell cycle regulating proteins, like p21, p27 (cyclin-CDK-inhibitors), CDK1, CDK2 (cyclin-dependent-kinases), and an induction of cell cycle arrest in G1/S and M/G2-phase in various cancer cells (13, 31, 32). Here, CDKN1A is linked to cancer.