In a cell–free assay with whole cell lysates from HCT116 human colon cancer cells, concentration–dependent inhibition of HDAC activity was observed by (S)–2HB and sodium butyrate (NaB) at 62.5, 125, 250, 500 and 1000 μM (Figure 6A), and by 0.625, 1.25, 2.5 and 5 μM 13(S)–HODE (Figure 6B). Here, HDAC9 is linked to colonic neoplasm.