Comparison of Topoisomerase-IIα Gene Status between Primary Breast Cancer and Corresponding Distant Metastatic Sites

Background. Topoisomerase-IIα (topo-IIα) is a key enzyme in DNA replication and a molecular target for anti-cancer drugs called topoisomerase-II inhibitors, such as anthracyclines. Its value as a predictive marker of responsiveness to these cytotoxic drugs is currently being evaluated with promising results. However, even in the metastatic setting, the choice of treatment is based on the biologic characteristics of the primary tumor. Few data are available regarding the expression of biological markers between the primary tumor and the corresponding distant metastases.