MCA performance in preoperative breast cancer patients

Mucin-like carcinoma-associated antigen (MCA) is a new tumor associated antigen expressed on breast cancer cells independent of histological type and recognized by a two-site sandwich EIA (Roche) using the Mab b-12 as capture and detection antibody and a MCA cut-off of 11 U/ml. MCA serum levels were determined in 409 breast cancer patients and in 100 pts with benign breast disease histologically confirmed and staged according to UICC. The sensitivity of MCA regarding the stage of disease was elevated only in metastatic patients (89%) and the MCA values of this group were significantly different compared to those of patients with early or locally advanced breast cancer. In the group of benign patients, the specificity was 81%. The correlation between MCA values and number of involved axillary lymph nodes showed significant differences in the O versus 4-10 node subgroup (p < 0.001), in O versus > 10 and in 1-3 versus 4-10 node subgroup (p < 0.05); elevated MCA sensitivity was found in the 4-10 and > 10 subgroups. In our experience, the determination of MCA is not useful for early diagnosis of breast cancer nor does it indicate the extent of lymph node involvement. With regard to the prediction of tumor recurrence in postoperative patients free of disease, MCA levels increased concomitantly with the clinical evidence of relapse. These findings suggest that the MCA assay is highly sensitive only in patients with metastatic breast cancer; therefore one of the most promising test application seems to be for monitoring the clinical course of advanced disease patients.