Breast cancer patients who inherit a "low activity" version of a certain gene may not benefit from tamoxifen as much as other breast cancer patients, according to researchers at the National Center for Toxicological Research in Jefferson, Arkansas.

Researchers analyzed the activity of the human sulfotransferase (SULT1A1) gene in 160 breast cancer patients who had been given tamoxifen and 177 women with breast cancer who were not given the drug.

The women treated with tamoxifen who inherited a "low activity" version of the SULT1A1 gene from both parents had three times the risk of death as those who were treated but had the normal version of the gene or had inherited the low activity gene from one parent.

Among women who were not given tamoxifen, there was no association between survival and the SULT1A1 gene, according to the report published in the Journal of the National Cancer Institute.

Other sources: Journal of the National Cancer Institute