DOES PREGNANCY IMMUNIZE AGAINST BREAST-CANCER

Multiparity has been linked with protection against breast cancer, T c ells from biparous women, but not T cells from nulliparous women or me n, specifically proliferated in response to core peptide sequences of a human breast cancer-associated mucin (MUC-1), Two of the nulliparous women were retested during the first trimester of their first pregnan cy, and their T cells proliferated specifically in response to MUC-1 m ucin, These observations support the hypothesis that there is a natura l immunization against MUC-1 peptide epitopes during pregnancy which p rovides some protection against the development of breast cancer, Thes e data also suggest that certain MUC-1 synthetic peptides might be eff ective components of ''vaccines'' for therapy or prevention of breast cancer.