JQKD 82 dihydrochloride is cell-permeable, selective inhibitor of lysine demethylase 5 (KDM5). JQKD 82 does not show activity toward other KDMs; and it has selectivity for KDM5A over other KDM5 isoforms. JQKD 82 causes hypermethylation of H3K4me3, downregulation of MYC targets and RNAPII phosphorylation; it suppresses multiple myeloma cell (MM.1S) growth (IC50 = 0.42 μmol/L). JQKD 82-treated tumors display an increase in H3K4me3 levels and results in a reduction of MYC immuno-staining in NSG mice.