Identifying Genes That Can Predict If Breast Cancer Drug is Working

Adding the drug trastuzumab to chemotherapy prevents cancer recurrence and improves survival in a large number of women with early stage HER2-positive breast cancer. But trastuzumab does not stop tumors from returning in about 25 percent of patients — and oncologists haven’t been able to identify these women before treatment. This situation may soon change, according to a Mayo Clinic study being presented at the 2012 CTRC-AACR San Antonio Breast Cancer Symposium.

A team of U.S. researchers, led by oncologists at Mayo Clinic’s campus in Florida, have discovered 27 genes that are significantly associated with a good outcome with concurrent use of trastuzumab and chemotherapy, as well as five other genes linked to a poor outcome using the same treatment regimen.

Results of their study — believed to be the first to use gene expression profiling to predict outcome to trastuzumab as part of adjuvant breast cancer therapy — offer a number of future potential benefits, says Edith Perez, M.D., deputy director at large of the Mayo Clinic Comprehensive Cancer Center and director of the Breast Cancer Translational Genomics Program at Mayo Clinic.

“These findings also are getting us closer to unraveling the biological factors that are relevant to patient outcome, which will help us improve clinical care,” Dr. Perez says.



Advances in the study of pharmacogenomics have resulted in development of tests to identify patients who would benefit from different treatment levels or the use of different drugs. Click  to learn more about the pharmacogenomics tests for oncology offered by Mayo Medical Laboratories (MML). Also, click the button below to view an MML Hot Topic on "The Use of Genetics in Guiding Therapy."


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