Clinical reversal of multidrug resistance.

The multidrug transporter, P-glycoprotein, is expressed in many human cancers and normal tissues [1–9]. Various aspects of the nature of mdr genes that encode P-glycoprotein and confer ‘classical’ multidrug resistance (MDR) are described in previous chapters in this volume. This chapter will focus on clinical implications of MDR and approaches to its reversal or modulation.