FUT4 and cancer: Glycan alterations vary depending on the type of cancer, but for N-glycans, they can include differential expression of blood group Lewis-related antigens such as Lewis X (LeX), Lewis Y (LeY), sialyl Lewis X (SLeX), and sialyl Lewis A (SLeA), increased synthesis of polylactosamine chains, increased β(1 → 6) branching of N-linked glycans, core α(1 → 6)-fucosylation, outer arm α(1 → 2)- and α(1 → 3)-fucosylation, and changes in sialylation, among others (11, 17, 18) (Figure 1A).