Predictive value of a gene signature evaluated in multiple chemotherapy regimens for breast cancer.
Approximately 12,800 U.S. women present with locally advanced breast cancer each year. Primary (or neoadjuvant) chemotherapy is a treatment to shrink a large tumor to a size that allows it to be removed with breast conserving surgery. A woman who would otherwise need a mastectomy (surgical removal of the breast) may instead elect to receive primary chemotherapy and breast- conserving lumpectomy. Unfortunately, primary chemotherapy has a low response rate (30%-50%) and a significant negative impact on a patient’s quality of life. If a tumor does not respond to primary chemotherapy, a mastectomy may be necessary after all. Currently, there is no widely used clinical test to determine before treatment if a given tumor will respond. We have developed a signature of 22 genes whose expression pattern accurately predicts response to primary chemotherapy in breast cancer.