Mucin-like carcinoma-associated antigen (MCA) in breast cancer: clinical experience at the National Cancer Institute of Milan.

Mucin-like Carcinoma-associated Antigen (MCA) is a glycoprotein belonging to the mucin family; it is defined by the monoclonal antibody b-12. Mucins represent an interesting group of tumor markers and are widely utilized in the clinical monitoring of neoplastic patients. These molecules show a certain degree of tissue specificity and MCA is preferentially associated with breast tissue. Several studies have demonstrated that patients with breast cancer usually have high MCA serum levels. In this paper the experience of the National Cancer Institute of Milan with the clinical use of MCA in breast cancer patients is reported. The observed sensitivity of the MCA test was poor in patients with early-stage disease, while it was acceptable in patients with advanced breast cancer. MCA concentrations appeared to be directly related to disease spread. A clear relationship was seen between MCA levels and lymph-nodal status. The highest MCA plasma levels were observed in patients with metastatic disease. In this group of patients the sensitivity of the test on the basis of a cut-off of 11 U/mL was 52%.