Multidrug resistance: an emerging threat

Abstract

Multidrug resistance (MDR) has been the main cause of failure of cancer chemotherapy where it is defined as the tendency of tumour cells to exhibit simultaneous resistance to unrelated chemotherapeutic agents. MDR has been mainly associated with the overexpression of an ATP binding cassette (ABC) protein, P-glycoprotein. Research in the past decade has revealed that the MDR phenomenon is not restricted to mammalian cells but rather occurs throughout the evolutionary scale. Thus over hundred ABC proteins have been characterized in mammals, bacteria and yeast. This review briefly describes the advancement in this field and identifies the problems which have emerged due to MDR.