CA15-3, CASA, MSA, AND TPS AS DIAGNOSTIC SERUM MARKERS IN BREAST-CANCER

This is the first comparison of the three mucin based tests CA15-3, CA SA, and MSA, and the cytokeratin-related TPS assay in breast cancer. T he mucin markers were superior to TPS in receiver-operator analysis, t hough no marker was of use in the diagnosis of malignancy due to low s ensitivity. Using cutpoints that gave 95% specificity in benign diseas e (n = 83), corresponding sensitivities in pre-treatment breast cancer (n = 123: 13 in situ, 54 stage I, 45 stage II, 4 stage III, 7 stage I V) were 17% (CA15-3), 16% (CASA), 13% (MSA), and 8% (TPS), with a stro ng relationship between marker levels and disease stage. These assays did not always detect the same patients, and the use of CA15-3 combine d with CASA gave the highest sensitivity (23%), though this was not si gnificantly better than the use of CA15-3 alone. Despite detecting sim ilar antigens, these assays can show markedly different responses in s ome patients, indicating that one mucin-based test cannot be substitut ed for another.