C1GALT1C1 and breast cancer: Moreover in the large METABRIC study, expression of COSMC was in fact increased in breast cancer compared to normal (1.5 fold, p = 5.15E-6) [34] suggesting that unlike that observed in pancreatic cancer [16], silencing of COSMC expression by DNA methylation may not play a role in dictating the expression of Tn and STn in breast cancer, although this can only be confirmed by determining the T synthase activity.