Is one of the most popular modifications with oligosaccharides on glycoproteins or glycolipid, which is involved in cancer. Fucosylation involves the attachment of a fucose residue to N-glycans, O-glycans, and glycolipids. O-fucosylation, which is a special type of fucosylation, is very important for Notch signaling. Increased levels of fucosylation have been reported in a number of pathological conditions, including inflammation and cancer. Therefore, certain types of fucosylated glycoproteins or antibodies, which recognize fucosylated oligosaccharides, have been used as tumor markers. The regulatory mechanisms of fucosylation are complicated.