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Detour Around the Estrogen Receptor

Study identifies factor that allows estrogen-dependent breast tumors to grow independently of estrogen

January 25, 2011 | Melissa Marino

About 75 percent of early-stage breast cancers are fueled by estrogen. These estrogen receptor (ER)-positive tumors typically respond to anti-estrogen therapies like tamoxifen, but about a quarter of patients develop resistance to these therapies and the tumors recur.

A multi-institutional team of researchers has now identified a potential new target for treating these tumors. The study, led by Ann Richmond, Ph.D., and colleagues at Tulane University, shows that increased expression of a “chemokine” receptor, CXCR4, allows estrogen-dependent breast tumors to grow independently of estrogen.

In human tumor samples, they show that increased expression of CXCR4 is correlated with poorer prognosis and decreased patient survival, regardless of ER status. They further show that inhibiting CXCR4 in a mouse model of breast cancer can reverse tumor growth and metastasis.

The results, reported in the Jan. 15 issue of Cancer Research, suggest that CXCR4 signaling is a rational target for the treatment of breast cancers that have become resistant to hormone therapies.

For other research highlights from Vanderbilt University Medical Center laboratories, see ‘Aliquots‘ in the VUMC Reporter.