Overexpression and knockdown studies of MUC1, revealed that it leads to increased tumorigenicity and anti-adhesive properties in number of systems including cancer cell lines of pancreas, breast, and myeloma, as well as in MUC1 transgenic model of human breast cancer and MUC1-transfected 3Y1 rat fibroblasts [12], [22]–[25]. This evidence concerns the gene MUC1 and breast cancer.