As CYP4Z1 is considered an EET synthase, it was therefore not surprising that the major products of internal oxidation of arachidonic acid (AA) in breast ductal carcinoma T47D cells engineered to express CYP4Z1 were derivatives 14,15-EET and 14,15-dihydroxy eicosatrienoic acid. This evidence concerns the gene CYP4Z1 and breast ductal adenocarcinoma.