It has been reported that anti-KL-6/MUC1 mAb increased aggregation of MUC1 glycoproteins at one pole of the cell, called capping of MUC1 on the surface and facilitated E-cadherin-mediated cell-cell interaction in breast cancer cell lines YMB-S and ZR-75-1S. This evidence concerns the gene MUC1 and breast cancer.