FUT4 encodes an alpha(1,3)-fucosyltransferase that catalyzes the synthesis of Lewis Y and related fucosylated oligosaccharides on glycoproteins and glycolipids. The enzyme is expressed during early human embryogenesis and continues in adult myeloid cells and brain tissue. FUT4 plays central roles in glycan-mediated cell adhesion and leukocyte migration through its regulation of carbohydrate epitopes on cell surfaces. FUT4 expression is transcriptionally regulated in a cell-type-specific manner through binding of HSF1 and Sp1 in breast cancer, and is suppressed by MyoD1 in gastric cancer 1 2. Recent evidence suggests FUT4 drives cancer progression across multiple malignancies by distinct mechanisms: in breast cancer, miR-493-5p suppresses FUT4 to reduce invasiveness 3; in melanoma, androgen-activated androgen receptor upregulates FUT4 to promote metastasis through L1CAM fucosylation and adherens junction disruption 4; in osteosarcoma, FUT4 inhibition activates FOXO1 and blocks Wnt/β-catenin signaling 5; and in cholangiocarcinoma, FUT4 overexpression drives epithelial-mesenchymal transition 6. Additionally, fucosylated haptoglobin derived from sepsis patients activates FUT4 expression in macrophage-like cells to amplify inflammatory responses 7. These findings suggest FUT4 inhibition or blocking FUT4-mediated glycosylation represent potential therapeutic strategies across cancer types and inflammatory disease.