Histone deacetylase (HDAC) inhibitors induce cell-cycle arrest, terminal differentiation and apoptosis in a broad spectrum of human tumour cell lines in vitro, and have antiangiogenic and antitumor activity in human xenograft models (Kim et al, 2001; Johnstone, 2002; Arts et al, 2003; Dokmanovic and Marks, 2005; Drummond et al, 2005). This evidence concerns the gene HDAC9 and neoplasm.