LLY-507 is a potent inhibitor of SMYD2 with IC50 < 15 nM, is >100-fold selective for SMYD2 over a broad range of methyltransferase and non-methyltransferase targets. IC50 value: < 15 nM Target: SMYD2 in vitro: LLY-507 shows the inhibitor binding in the substrate peptide binding pocket. LLY-507 is active in cells as measured by reduction of SMYD2-induced monomethylation of p53 Lys370 at submicromolar concentrations. LLY-507 inhibits the proliferation of several esophageal, liver, and breast cancer cell lines in a dose-dependent manner. LLY-507 serves as a valuable chemical probe to aid in the dissection of SMYD2 function in cancer and other biological processes.