– 4-oxo Docosahexaenoic acid (4-oxo DHA) is a putative metabolite of DHA with antiproliferative and PPARγ agonist activity. It inhibits the growth of several triple-negative breast cancer cell lines [MCF-10F, trMCF, bsMCF, MDA-MB-231, and BT549] at 50-100 μM but increases the proliferation of MCF-7 cells. 4-oxo DHA binds covalently to PPARγ and activates gene transcription in luciferase reporter assays and dendritic cells with EC50 values of approximately 8-16 μM.