Lewis B antigen; Lewis Y antigen (Le^b^ (Lewis B); Le^y^ (Lewis Y))

Lewis B and Lewis Y antigens are **difucosylated oligosaccharide blood group antigens** created by the action of fucosyltransferases (FUT2, FUT3) on precursor chains[1][4][7][10]. Lewis B antigen is formed via sequential fucosylation in individuals who possess both FUT2 (secretor) and FUT3 (Lewis) activities, while Lewis Y antigen is a structurally related tetrasaccharide primarily detected on cell surface glycoconjugates[1][4]. Lewis Y is commonly found during embryogenesis and is rarely expressed on adult cells except for certain epithelial tissues and granulocytes[1][8]. Both antigens are *overexpressed in numerous epithelial cancers*, where they participate in tumor cell proliferation, adhesion, migration, and metastasis, partly by modifying surface receptor functions and activating signaling pathways such as PI3K/Akt[3][6]. Because of their restricted normal tissue distribution and upregulation in malignancy, **Lewis Y has become a notable immunotherapeutic target**, with several monoclonal antibody drugs undergoing clinical investigation for targeting Lewis Y-positive tumors[2][5][8]. Both antigens also serve as disease biomarkers, aiding in cancer diagnosis and patient stratification[3]. The biologic and clinical significance of Lewis B and Lewis Y antigens centers around their dual role in normal glycan biology and as markers/drivers of malignant transformation and cancer progression[1][3][4][6][8][10].

Other names

Le^b^Lewis b antigenLe^y^Lewis y antigen

Antibody-mediated cytotoxicity against antigen-positive tumor cells Inhibition of cell proliferation and migration via blockade or modification of glycan structures (e.g., by anti-Lewis Y antibodies, fucosidase) Interference with signal transduction pathways (PI3K/Akt, EGFR)