The Expression of ERβcx in Human Breast Cancer and the Relationship to Endocrine Therapy and Survival

Carlo Palmieri, Eric W.F. Lam, Janine Mansi, Claire MacDonald, Sami Shousha, Peter Madden, Yoko Omoto, Andrew Sunters, Margaret Warner, Jan Åke Gustafsson, R. Charles Coombes

Research output: Contribution to journalArticlepeer-review

57 Scopus citations


Purpose: Estrogen receptor (ER) α-positive breast cancer is often treated with endocrine therapy using either antiestrogens or aromatase inhibitors. However, 30% of patients who receive endocrine therapy will derive no benefit from such treatments and may indeed suffer adverse effects. Currently, there are no ways to predict response to such treatments. ERβcx, a variant of ERβ, has a dominant-negative effect over ERot, and its expression thought to modulate response to endocrine treatment may represent a predictor of response to endocrine therapy. Experimental Design: We investigated the expression of the ERβcx in 82 frozen breast samples (8 benign, 1 ductal carcinoma in situ, and 73 malignant) by Western blot analysis. The relationship between the expression of ERβcx variants with prognosis and outcome of endocrine therapy was examined. Results: There was a statistically significant association between the presence of ERβcx and the response to endocrine therapy (Fisher's exact test, P = 0.04). We also examined the influence of the ERβcx status of a tumor on time to progression and death. There was a relationship between the presence of ERβcx and survival, with patients whose tumors express ERβcx having a longer survival rate (P = 0.05). Cell-type specificity of expression was assessed by immunohistochemistry on a selection of histological samples. Conclusions: On the basis of this small group of patients, we conclude that the expression of ERβcx correlated with favorable response to endocrine therapy. A larger study involving the staining of archival material is currently underway to confirm these preliminary results.

Original languageEnglish (US)
Pages (from-to)2421-2428
Number of pages8
JournalClinical Cancer Research
Issue number7
StatePublished - Apr 1 2004

ASJC Scopus subject areas

  • Oncology
  • Cancer Research


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