To investigate whether the expression of RTK depends on HDAC class I and II activity, leukemia cells Kasumi-1, K562, THP-1, HL-60, and NB cells LAN-1, SH-SY5Y, and Kelly were incubated with cytotoxic concentrations (according to IC50 value for hydrazostat for each cell line) of belinostat and hydrazostat for 72 h. Here, HDAC9 is linked to leukemia.