APOE, or apolipoprotein E, is a protein that plays a critical role in the metabolism of lipids and cholesterol in the body. Research in the field of APOE focuses on its genetic variations and their associations with various health conditions, particularly Alzheimer's disease and cardiovascular diseases. The APOE gene has three common alleles (e2, e3, and e4), with the e4 allele being associated with an increased risk of developing Alzheimer's disease and a higher risk of cardiovascular diseases. Studies in this research area aim to better understand the mechanisms by which APOE gene variations influence disease risk and to develop potential therapeutic interventions based on this knowledge.