The aim of the present study was to evaluate the clinical value of the new tumour marker
TAG 12 in sera from patients with
breast cancer (n = 123), patients with benign
breast disease (
n = 30) and normal controls (n = 38). The results for
TAG 12 were compared with those for CA 15-3 and MCA. The cut-off levels (90% specificity) determined for each test in the benign and control groups were 57.5 kU/1 for
TAG 12, 24.8 kU/1 for CA 15-3 and 11.8 kU/1 for MCA. The diagnostic sensitivity of the
TAG 12 test was 0.30, 0.19 for CA 15-3 test and 0.20 for MCA test in detecting
breast cancer.
TAG 12, CA 15-3 and MCA tests were tested in a multivariate analysis to find the best combination of independent predictors of
breast cancer. The most important predictor of
breast cancer was
TAG 12. In order to evaluate the contributions of different tumour
marker serum tests a stepwise discriminant analysis was carried out. The discriminant function is DF =
TAG 12 x 0.0349 + CA 15-3 x 0.0568 + MCA x (-0.33) - 0.53. The sensitivity of the DF in detecting
breast cancer was 31% with a specificity of 91% and a efficiency of 52%. The correlation coefficient in
breast cancer patients between
TAG 12 and CA15-3 measurements was 0.95, and 0.90 between
TAG 12 and MCA measurements. In conclusion, the results indicate that
TAG 12, CA 15-3 and MCA have only limited value in the diagnosis of
breast cancer, but their role in monitoring and follow up of
breast cancer patients is a subject for further investigation.