MUC1 and breast cancer: It is known that MUC1-C homodimers can be transported to the nucleus and mitochondria, resulting in diverse cellular behaviors such as inefficient transcription of p53 genes and the inhibition of apoptosis due to the direct binding of MUC1-C and p53 [7]; the inhibition of cell adhesion and migration resulting from the reduction of the E-cadherin/β-catenin complex [8,9,10,11]; and the loss of apical-basal polarity in breast cancer cells.