Additionally, cell studies of the combined histone deacylase (HDAC) inhibitors 25 and 26 with fluorouracil, an isosteric replacement for pyridine against HDAC protein source (Hela cell nuclear extract), resulted in inhibitory potentials of 5.92 and 2.31 μM for compounds 25 and 26 compared to the moderate anti-proliferative activity estimated with seven tumor cell panels (K-562, A549, U266, PC-3, HCT-116, ES-2, and HL-7720) [46]. Here, HDAC9 is linked to neoplasm.