CA 15-3, for Cancer Antigen 15-3 [1] , is a tumor marker for many types of cancer, most notably breast cancer. [2] [3] [4]
It is derived from MUC1. [5] CA 15-3 and associated CA 27-29 are different epitopes on the same protein antigen product of the breast cancer-associated MUC1 gene.
Elevated CA15-3, in conjunction with alkaline phosphatase (ALP), was found to be associated with an increased chance of early recurrence in breast cancer. [6]
Both CA 15-3 and CA 27-29 may be elevated in patients with benign ovarian cysts, benign breast disease, and benign liver disease. Elevations may also be seen in cirrhosis, sarcoidosis and lupus.