CANCER ANTIGEN 15-3- CA 15-3

The CA 15-3 is an epitope on a large mucin-like glycoprotein, which is a product of polymorphic epithelial mucin called MUC1. In breast cancer, the MUC1 mucin becomes aberrantly glycosylated, over expressed and released into circulation, as a consequence elevated CA 15-3 levels can be detected. Elevated levels of CA 15-3 antigen may also be present in those patients with non- malignant conditions such as cirrhosis, hepatitis, autoimmune disorders and benign diseases of ovary and breast.
CA 15-3 antigen has become a widely recognized breast cancer marker and has been shown to be more sensitive than CEA. The CA 15-3 assay may be of clinical value for monitoring the conditions of breast cancer patients undergoing therapy, as the increasing and decreasing values are correlated with disease progression and regression, respectively.