FUT4 and neoplasm: LeX carbohydrate structures are described to be expressed in the brain (Lieberoth et al., 2009), and can be de novo expressed on cancer stem cells (Read et al., 2009) or pathogens, and the glycosylation pattern of in vivo accumulating antigens, being brain tissue, tumor tissue or pathogen structure, is crucial for directing specific CLR antigen uptake and cross-presentation (Hittelet et al., 2003; Ohana-Malka et al., 2003).