Expression analysis of estrogen receptor alpha coregulators in breast carcinoma: evidence that NCOR1 expression is predictive of the response to tamoxifen

Igor Girault, Florence Lerebours, Samira Amarir, Sengül Tozlu, Michèle Tubiana-Hulin, Rosette Lidereau, Ivan Bièche
Clinical Cancer Research 2003, 9 (4): 1259-66

PURPOSE: Dysregulated expression of steroid receptor transcriptional coactivators and corepressors has been implicated in tamoxifen resistance, especially in estrogen receptor (ER) alpha-positive breast cancer patients. Therefore, expression analysis of these ERalpha coregulators may identify new predictors of the response to tamoxifen treatment.

EXPERIMENTAL DESIGN: We measured mRNA levels of 16 coactivator and 11 corepressor genes with a real-time quantitative reverse transcription-PCR method in 14 ERalpha-positive breast tumors. Three selected coactivator genes (TIF2, AIB1, and GCN5L2) and two corepressor genes (NCOR1 and MTA1L1) were additionally investigated in a well-characterized series of ERalpha-positive unilateral invasive primary breast tumors from 99 postmenopausal patients who only received tamoxifen as adjuvant hormone therapy after primary surgery. We sought relationships between mRNA levels of the coregulators and those of molecular markers, including ERalpha, ERbeta, CCND1, and ERBB2.

RESULTS: ERalpha coregulator expression was unrelated to age, histological grade, lymph node status, and macroscopic tumor size. The relationship between mRNA expression of the coregulators, and ERalpha and beta only showed a significant positive correlation between GCN5L2 and ERalpha (P = 0.015). mRNA levels of CCND1 correlated with those of all of the coregulators studied (P < 0.05 or trend), whereas ERBB2 mRNA levels only correlated with AIB1 mRNA levels (P = 0.011). Low NCOR1 expression (versus intermediate and high) was associated with significantly shorter relapse-free survival (log-rank test; P = 0.0076). The prognostic significance of low NCOR1 expression persisted in Cox multivariate regression analysis (P = 0.043).

CONCLUSIONS: These findings point to NCOR1 as a promising independent predictor of tamoxifen resistance in patients with ERalpha-positive breast tumors.

Full Text Links

Find Full Text Links for this Article


You are not logged in. Sign Up or Log In to join the discussion.

Trending Papers

Remove bar
Read by QxMD icon Read

Save your favorite articles in one place with a free QxMD account.


Search Tips

Use Boolean operators: AND/OR

diabetic AND foot
diabetes OR diabetic

Exclude a word using the 'minus' sign

Virchow -triad

Use Parentheses

water AND (cup OR glass)

Add an asterisk (*) at end of a word to include word stems

Neuro* will search for Neurology, Neuroscientist, Neurological, and so on

Use quotes to search for an exact phrase

"primary prevention of cancer"
(heart or cardiac or cardio*) AND arrest -"American Heart Association"