Docosapentaenoic acid (DPA) is a 22-carbon fatty acid found in fish oils. It is a minor constituent of the total serum unsaturated fatty acids in humans, ranging from 0.1 to 1%, and increases on dietary supplementation. all-cis-4,7,10,13,16-DPA, also known as osbond acid, is an isomer of DPA. It is an ω-6 fatty acid formed by the elongation and desaturation of arachidonic acid . Levels of this fatty acid may be diminished during fatty acid desaturase syndrome and this may affect development. Upregulated expression of hepatic elongation of very long fatty acids protein 6 and increased levels of very long chain fatty acids, including all-cis-4,7,10,13,16-DPA, are characteristic of non-alcoholic steatohepatitis, a preneoplastic condition of hepatocellular carcinoma.