An EZH2 inhibitor (IC50 11 nM) inhibits mutant EZH2 including EZH2A677G EZH2A687V and EZH2Y641F and EZH2Y641S (IC50s 2 2 14 and 4 nM respectively) selective for wild-type and mutant EZH2 over EZH1 (IC50 392 nM) and a variety of other histone methyltransferases (IC50s 50 or 100 UM for all) reduces H3K27me3 levels in various lymphoma cell lines expressing wild-type or mutant EZH2 (IC50s 2-8 and 2-22 nM respectively) inhibits proliferation of various lymphoma cell lines expressing wild-type or mutant EZH2 (IC50s 0.099-6.2 and 0.00049-5.8 UM respectively) induces insulin production and glucose-stimulated insulin secretion in human pancreatic exocrine cells isolated from juvenile patients with type 1 diabetes or adults without diabetes at 1 UM reduces H3K27me3 levels and induces insulin secretion and glucose-stimulated insulin secretion in human pancreatic ductal epithelial cells in vitro