The positivity of 16A mAb staining in breast cancer (90%) is greater than that of SAR566658,30, 31, 32 which binds to a sialylated unknown MUC1 sequence in bladder, breast, ovary, pancreatic, head, and neck cancers with positivity rates of 59%, 29%–35%, 70%, 59%, and 17%, respectively. The gene discussed is MUC1; the disease is breast carcinoma.