MUC1 and cancer: Cancer-derived MUC1 stimulates both humoral and cellular immunity, its normal apical distribution is lost in cancer cells and aberrant glycosylation exposes peptide epitopes and novel carbohydrate antigens such as Thompson-Friedenreich (TF: Gal(1-3)-α-GalNAc-O-serine/threonine) and Tn, the monosaccharide precursor of TF (α-GalNAc-O-serine/threonine)), which are not found in normal tissues [12,13,14].