FUT4 and breast cancer: Our previous study indicated that FUT4 promoted the proliferation and metastasis abilities of cancer cells, including breast cancer,12 non-small cell lung cancer13 and melanoma.14 Silencing of FUT4 by specific siRNA decreased the proliferation of A431 cells,47 and FUT4 inhibited epithelial–mesenchymal transition of MCF-7 and MDA-MB-231 cells.32 In this study, FUT4 expression level was correlated with the clinical stages of breast cancer in a tissue chip assay (Table 1, Figure 1a).