MUC1 and neoplasm: The study indicated that combined measurement of blood tumor biomarkers—including CEA, mucin-1 antigens (CA15-3 or CA27.29), and erythrocyte sedimentation rate (ESR)—provides significant value for diagnosing metastatic breast cancer and monitoring treatment response, outperforming single-marker assays and demonstrating strong concordance with conventional UICC criteria.