Molecular mechanisms of Lewis antigen expression

Lewis antigens comprise type 1 (Lewis a, Lewis b) and type 2 (Lewis X, Lewis Y) carbohydrates. Lewis X and Lewis Y are regarded as tumor-associated markers, and some of these antigens and their derivatives interact with selectins, mediating cell-to-cell adhesion. In addition, Lewis b on the gastric epithelial surface has been identified as an acceptor for attachment of Helicobacter pylori. In this review, we describe the regulation the expression of type 1 Lewis antigens on erythrocytes or digestive organs by two genes (FUT2 and FUT3), and the ethnic specificity of the polymorphism of these genes for forensic use.