The comparison of five established tumor markers CEA, CA 15-3, CA 125, CA 19-9 and AFP assessed on a novel multiplex immunoassay platform and on an automatized routine method using a LOCI-technology platform in samples from breast cancer patients and control cohorts yields acceptable correlations for CEA, CA 15-3 and AFP while they are lower for CA 125 and CA 19-9. The gene discussed is CEACAM5; the disease is breast carcinoma.