Expression of MUC1, MUC2 and oligosaccharide epitopes in breast cancer: prognostic significance of a sialylated MUC1 epitope.

MUC1 represents a promising marker in breast cancer. However, due to the structural complexity of the MUC1 glycoprotein, multiple epitopes can be detected by monoclonal antibodies. This fact may be responsible for the contradictory results of previous investigations regarding the clinical and prognostic relevance of MUC1 expression in breast cancer.