Clinical significance of the new tumor marker MCA in the follow-up of patients with mammary carcinoma.

MCA is a mucin-like carcinoma-associated antigen which has been found in all breast cancer independent of histological type and degree of differentiation. A two-step solid-phase EIA was developed and the serum concentration of MCA was measured in 176 breast cancer patients after surgery. Using a cutoff of 11.0 U/ml the test showed a sensitivity of 77% and a specificity of 82% when compared to clinical status. The predictive value of this tumor marker was 72% for a positive diagnosis and 93% for a negative diagnosis. Based on these observations it is recommended that determination of MCA values take place 2 to 3 times in the first postoperative week in all women with surgically treated mammary carcinoma. These MCA values should then serve as reference for further determinations, which should be performed at each check-up. A subsequent increase in the MCA value should be considered as a first sign of metastasis.