PROGNOSTIC-SIGNIFICANCE OF MUC1 EPITHELIAL MUCIN EXPRESSION IN BREAST-CANCER

The epithelial mucin produced by the MUCl gene is present in the apical cell membrane of normal breast epithelial cells and is highly expressed in many breast cancers. Several studies have provided conflicting evidence regarding the relationship between MUCl expression and survival in breast cancer patients. In this study a detailed immunohistological analysis of MUCl expression was performed using monoclonal antibody BC2 and was related to other tumor characteristics: and patient survival. Patients whose tumors showed MUCl expression in greater than 75% of tumor cells had significantly poorer disease-free and overall survival (P < .05). The proportion of cells showing cytoplasmic MUCl expression was prognostically significant, but the proportion of cells that lined gland spaces showing apical membrane staining was of no prognostic significance. A high level of MUCl expression was significantly associated with the presence of axillary node metastases and estrogen recep tors but not with other tumor characteristics. HUM PATHOL 26:432-439. Copyright (C) 1995 by W.B. Saunders Company