TP53 and small cell carcinoma: Acetylation of p53, which may be caused by HDAC inhibitors, decreases generation of a complex p53/Mdm2 E3 ligase, whereas hypoacetylation increases its degradation by the proteasome and cancels p53-mediated growth arrest and apoptosis as demonstrated by experiments with human non-small cell carcinoma cells H1299 transfected by different Tp53 mutants [48].