The obtained potential HDAC inhibitors based on a N-hydroxy-(4-oxime)-cinnamide scaffold (including isoxazoline presented in Scheme 63) were preliminarily tested as far as their in vitro cytotoxic activity on three tumor cell lines, NB4, H460 and HCT116, as well as their inhibitory activity against class I, II, and IV HDAC, are concerned. This evidence concerns the gene HDAC9 and neoplasm.