CAY10770 is an inhibitor of the cytochrome P450 (CYP) isoform CYP4Z1 (IC50= 5.9 μM).1It is selective for CYP4Z1 over CYP4A11, CYP4F2, CYP4F3a, CYP4F3b (IC50s = 187-282 μM) but does inhibit CYP4F8 and CYP4F12 (IC50s = 167 and 91 μM, respectively). CAY10770 (3 μM) inhibits the production of 14(15)-EET, 19-HETE, and 14(15)-DiHET by 83, 86, and 80%, respectively, in T47D breast cancer cells expressing CYP4Z1.