Mucin-like Carcinoma-associated Antigen (MCA) has been associated with many breast
cancers. The aim of this study was to evaluate MCA in
tumor tissue and serum as a potential
tumor marker for prognosis and disease monitoring. MCA levels were determined in the tissue of 196 patients with primary
breast cancer, 25 with metastatic disease and 25 patients with benign diseases, in pellet and/or cytosol. MCA levels were also determined in the serum of 50 patients with benign diseases, 148 with primary
breast cancer (Mo), 150 with metastatic
breast cancer (MT), and 200 with no clinical evidence of disease (NED). MCA tissue concentrations in pellet and cytosol were similar: 66.7 + 251 U/mg and 41.1 + 53 U/mg, respectively. No relationship between MCA levels and
tumor size or nodal involvement was found. Higher MCA levels were observed in patients with ER+ or PgR+
tumors than in those with ER- or PgR-
tumors (p < 0.01). Patients with MCA pellet concentrations lower than 10 U/mg of
protein had shorter disease-free intervals (DFI) than those with higher values (p < 0.05). Abnormally high serum levels of MCA were found in 8% of patients with benign diseases, 4% of NED patients, 22% of Mo patients, and in 76% of MT cases. In primary
breast cancer MCA values were related to
tumor size and nodal involvement. A trend toward a lower DFI in patients with elevated presurgical MCA levels was observed but was of no statistical significance. These differences became statistically significant when patients were subdivided according to nodal status, with shorter DFI in those without nodal invasion (p < 0.05). In metastatic patients, changes in serum MCA were related to the
tumor's response to treatment in 82% of cases. The highest MCA values were found in patients with liver or bone
metastasis and the lowest values were found in those with locoregional recurrence. In conclusion, although MCA is not a specific
tumor marker, it can be useful as a prognostic factor (tissue and serum) and in monitoring metastatic patients.