MUC1 is expressed at high frequency in early-stage basal-like triple-negative breast cancer

Hum Pathol. 2013 Oct;44(10):2159-66. doi: 10.1016/j.humpath.2013.04.010. Epub 2013 Jul 8.


Triple-negative breast cancer comprises 10% to 15% of newly diagnosed breast cancer and lacks expression of the estrogen, progesterone, and human epidermal growth factor receptor 2/neu receptors. Many such tumors are basal like, a molecular intrinsic subtype of breast cancer associated with poor clinical outcomes. Patients with early-stage basal-like triple-negative breast cancer are at a high risk for relapse and may, therefore, benefit from novel therapies, including immunotherapy. MUC1 is a tumor antigen expressed on adenocarcinomas and represents an ideal target for MUC1-based vaccination. We evaluated 52 cases of early-stage basal-like triple-negative breast cancer for MUC1 expression by immunohistochemistry. The intensity of staining was graded according to the intensity (negative [0], positive [1], or strongly positive [2]) and percentage (0%-100%) of tumor cells staining for MUC1. An overall score of 0 to 2.0 was calculated for each case by multiplying the intensity of staining by the percentage of tumor cells staining positively. Four staining patterns for MUC1 were identified: apical, cytoplasmic, membranous, and combination. Of the 52 cases of basal-like triple-negative breast cancers, 49 (94%) were positive for MUC1 expression. The mean score was 0.90 (range, 0-1.9). Cases were evenly distributed over this range, where most (67%) exhibited moderate to strong MUC1 expression (score, 0.5-1.90), 27% demonstrated weak MUC1 expression, and 6% lacked MUC1 expression. There was a significant difference in MUC1 score and percent MUC1+ cells in favor of the combination pattern. This study indicates that a large proportion of early-stage basal-like triple-negative breast cancer expresses MUC1 and provides a rationale for MUC1-based immunotherapy in this high-risk patient cohort.

Keywords: Basal-like; Mucin; Triple-negative breast cancer.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Adenocarcinoma / metabolism*
  • Adenocarcinoma / pathology
  • Adult
  • Aged
  • Aged, 80 and over
  • Biomarkers, Tumor / metabolism
  • Breast Neoplasms / metabolism*
  • Breast Neoplasms / pathology
  • Early Diagnosis
  • Female
  • Humans
  • Middle Aged
  • Mucin-1 / metabolism*
  • Neoplasm Staging
  • Receptor, ErbB-2 / metabolism*
  • Receptors, Estrogen / metabolism*
  • Receptors, Progesterone / metabolism*


  • Biomarkers, Tumor
  • MUC1 protein, human
  • Mucin-1
  • Receptors, Estrogen
  • Receptors, Progesterone
  • Receptor, ErbB-2