Inhibition of HDAC activity causes cell cycle arrest and apoptosis in cancer cells, primarily through transcriptional activation of p53-mediated pro-apoptotic response and induction of cell cycle kinase inhibitor p21/waf1 and Bax, as well as through transcriptionally-independent direct binding of p53 to Bax, Bcl2 and Bcl-xL[12], [13]. Here, TP53 is linked to cancer.