Peptide Epitopes in Breast Cancer Mucins

Abstract

Major advances have occured in the structural analysis of mucins found in breast cancer following the isolation of cDNAs and the gene for MUC1 - which is the predominant mucin expressed in breast cancer^1-4. In addition, other genes coding for mucins have been identified which are expressed in a variety of tissues, and are also found in breast tissue and to a lesser extent in breast cancer (particularly MUC2 and MUC3)^{5, 6} It was of interest that these genes were isolated using polyclonal antibodies and bacterial expression libraries, indicating that the active antibodies were detecting a non-glycosylated linear peptide, and this prediction was proven by the finding that many existing anti-MUC1 monoclonal antibodies react with synthetic peptides. The focus of this review will be to determine whether: a) monoclonal antibodies made against tumors react with peptides and what epitopes are detected (particularly for MUC1); b) if anti-pep tide antibodies can be made which react with cancers (MUC1,2, 3); c) second generation antibodies can be made to fusion proteins (MUC1); d) and what epitopes are detected with all of these antibodies; e) finally, what are the implications of these new advances in the diagnosis and treatment of breast cancer.