Useful ForáSuggests clinical disorders or settings where the test may be helpful
FDA-approved cancer-associated antigen (CA 27.29) for serial testing in women with prior stage II or III breast cancer who are clinically free of disease
áPredicting early recurrence of disease in women with treated carcinoma of the breast
áAs an indication that additional tests or procedures should be performed to confirm recurrence of breast cancer
Carcinoma of the breast is the most prevalent form of cancer in women. These tumors often produce mucinous antigens that are large-molecular-weight glycoproteins with O-linked oligosaccharide chains.
áMonoclonal antibodies directed against these antigens have been developed, and several immunoassays are available to quantitate the levels of tumor-associated mucinous antigens in serum. The antibodies recognize epitopes of a breast cancer-associated antigen encoded by the human mucin 1 (MUC-1) gene, which is known by several names including MAM6, milk mucin antigen, CA 27.29, and cancer antigen 15-3 (CA 15-3).
While CA 27.29 is expressed at the apical surface of normal epithelial cells, it is present throughout malignant epithelial cells of the breast, lung, ovary, pancreas, and other sites. The cancer-associated form of the antigen is less extensively glycosylated than the normal form and more specific for tumor cells.
> or =18 years: < or =38.0 U/mL (use not defined)
> or =18 years: < or =38.0 U/mL
Reference values have not been established for patients who are <18 years of age.
Serum markers are not specific for malignancy, and values may vary by method.
Increased levels of cancer-associated antigen (CA 27.29) (>38 U/mL) may indicate recurrent disease in a woman with treated breast carcinoma.
This test provides results on female patients only at this time.
áThe use of cancer-associated antigen (CA 27.29) has not been demonstrated to provide clinical benefit to these patients, which has led some Mayo clinical investigators to conclude there is insufficient justification for routine clinical use of this new marker.
áMeasurement of CA 27.29 is not useful to screen women for carcinoma of the breast.
áSome patients who have been exposed to mouse antigens, either in the environment or as part of treatment or imaging procedure, may have circulating antimouse antibodies present. These antibodies may interfere with the assay reagents to produce unreliable CA 27.29 results.