CETP (Cholesteryl Ester Transfer Protein) is a crucial protein that facilitates the transfer of cholesterol esters and triglycerides in the plasma. It is mainly expressed in the liver and plasma, playing an important role in regulating the lipid composition and concentration of HDL (high-density lipoprotein) and LDL (low-density lipoprotein). The activity of CETP is essential for reverse cholesterol transport and systemic lipid metabolism. Variations in gene expression levels and activity are associated with the risk of cardiovascular diseases. Specific genetic mutations may lead to reduced CETP activity, which is associated with increased levels of HDL and decreased risk of cardiovascular diseases.