Of these, three genes have higher expression in the tumor tissues including ST6GALNAC5 (2.31-folds), ST8SIA3 (1.78-folds) and ST8SIA4 (2.47-folds) (Figures 2d and f), suggesting that breast cancer expressed high levels of α2,6- and α2,8-linked sialylation. Here, ST8SIA4 is linked to breast cancer.