IRF1 and colonic neoplasm: PPARa binds a variety of fatty acids 67,68 and is involved in lipid metabolism as well as nutrient transport and energy; it also plays a protective role against colon cancer 69,70 Ppara was upregulated by all three HFDs in the small intestines, as was Cd36, a fatty acid transporter and target of PPARa 71 The other most prominent transcription factor family that was dysregulated by the HFDs were the STAT/IRF factors involved in interferon signaling (Stat1, Stat3, Irf1, Irf5, Irf8) and hence play a critical role in the immune system.