MUC1 and breast cancer: Detection of glycosylation cancer-associated mucin 1, mucin 16 and CD63 may contribute to the accurate and effective differentiation of primary breast cancer.374 Inadequate glycosylation of MUC1 leads to exposure to novel epitopes that can be used as specific targets for treatment and diagnosis.375 The subcellular localization of tumor-associated MUC1 is significantly different from that of normal cells.