The apolipoprotein E (APOE) gene is a gene that encodes a protein involved in the regulation of cholesterol metabolism. Variations in the APOE gene have been associated with an increased risk of developing Alzheimer's disease and cardiovascular disease. Research in this area focuses on understanding the role of APOE gene variants in these diseases, as well as exploring potential therapeutic targets related to APOE. Additionally, studies are investigating the impact of the APOE gene on other conditions such as cognitive decline and neurodegenerative disorders.