[Overcoming of multidrug resistance and its clinical application]

P-glycoprotein plays a key role in the mechanisms of multidrug resistance in experimental tumors as well as in clinical tumors in acquired-type resistance and in intrinsic-type resistance. Thus the therapeutic approaches targeting the P-glycoprotein would provide benefits in eradication of drug-resistant tumor cells. Practical approaches to overcoming of multidrug resistance by targeting the P-glycoprotein would be; to use agents including calcium channel blocker-related agents and membrane-modifying agents that interact with P-glycoprotein, although some potential problems concerning side effects still remained to be studied.