The CGA gene as new predictor of the response to endocrine therapy in ER alpha-positive postmenopausal breast cancer patients.

We recently identified CGA (coding for the alpha subunit of glycoprotein hormones) as a new estrogen receptor alpha (ER alpha)-responsive gene in human breast tumors. Here, we assessed the relationship between CGA status (as determined by real-time quantitative RT-PCR) and the response to tamoxifen therapy in a well-defined cohort of 125 ER alpha-positive postmenopausal breast cancer patients treated with primary surgery followed by adjuvant tamoxifen alone. CGA overexpression, observed in 37.6% of patients, was associated with good relapse-free survival (P=0.037; univariate analysis). CGA status, combined with ERBB2 status (a marker of poor outcome), was an independent predictor of the response to tamoxifen (P=0.020; multivariate analysis). CGA status, especially when combined with ERBB2 status, may thus provide useful predictive information on tamoxifen responsiveness in breast cancer.