Cancer Ag 15-3

Cancer Antigen 15-3 (CA 15-3) is a tumor marker protein elevated in some cancers, particularly breast cancer. This qualitative test detects the presence or absence of elevated CA 15-3 levels. While elevated levels may indicate breast cancer or other malignancies, CA 15-3 can also be elevated in benign conditions like liver disease or endometriosis, making it unsuitable as a screening test. It is primarily used to monitor treatment response or detect recurrence in known cancer patients.