cis-4-Br-2,5-F2-PCPA (S1024) inhibits LSD1 and LSD2 with Ki values of 94 nM and 8.4 μM, respectively. It inhibits LSD1 cell proliferation and increases dimethylated histone H3 at K4 (H3K4) in CCRF-CEM cells, particularly where there is aberrant expression of LSD1 in cancer stem cells [1].