June 4, 2004

Genes key to breast cancer
recurrence risk

A simple measurement of the activation of two genes in breast cancer tissue appears to identify tumors that are more likely to recur in women treated with the drug tamoxifen for early-stage disease. Determining patients for whom tamoxifen treatment is likely to fail would allow earlier use of other therapies that could be more effective for those women. Researchers from the MGH Cancer Center and Arcturus Bioscience, Inc., describe their findings in a report to be published in the June issue of Cancer Cell and released online June 3.

"Until now, there has been no way to predict which estrogen-receptor-positive patients will not respond to tamoxifen treatment. The ability to do so could allow physicians to choose other drugs for those patient," says Dennis Sgroi, MD, director of Breast Pathology at the MGH.

The researchers gathered tumor samples from patients who had received tamoxifen treatment for early-stage, estrogen-receptor-positive breast cancer. Detailed analysis of which genes were expressed or "turned on' in the tumors demonstrated that the ratio between the expression levels of two genes — HOXB13 and IL17BR — was the strongest predictor of whether a tumor would recur. The first analysis of samples from 60 patients was followed by analyses of tumors from 20 other patients, and data from both groups supported the predictive power of the two-gene expression ratio.

A commercial analysis based on these findings may be available later this summer. Other MGH authors of the study are Zuncai Wang, PhD, Paula Ryan, MD, PhD, Anne Barmettler, Andrew Fuller, Beth Muir, Gayatry Mohapatra, PhD, Barbara Smith, MD, PhD, Jerry Younger, MD, Ulysses Balis, MD, Atul Bhan, MD, Karleen Habin, RN, and Daniel Haber, MD, PhD.