Multi-drug resistance as a problem challenging breast cancer chemotherapy

Success in breast cancer chemotherapy is challenged by the development of tumors having a multi-drug resistance (MDR) phenotype. It is one of the major causes of failure to cancer chemotherapy. MDR is a multi-factorial problem, where several mechanisms are acting in concert with each other for the development of MDR phenomenon. Though many of the underlying mechanisms are still not clearly identified, several potential molecular targets and pathways of activation have been suggested. The advances in this field provide an emerging picture of how MDR arises and how it could be therapeutically targeted. In this chapter, we review recent experimental and clinical evidence of the different molecular basis of MDR. Also, we review the relevance of using different MDR inhibitors (benefits and problems).