MUC1 and breast carcinoma: Interestingly, overexpression of MUC1 in human breast cancer lines as well as murine lines results in decreased expression of the extension enzymes core 2 β1,6-N-acetylglucosaminyl transferase 1 (C2GnT1) and ST3 β-galactosidase α-2,3-sialyl transferase 1(ST3Gal1) suggesting that MUC1 can potentiate expression of truncated glycans in a feed forward manner [100].