REVERSAL OF MULTIDRUG RESISTANCE OF TUMORS

Multidrug resistance (MDR) describes the simultaneous expression of resistance of tumors to a wide range of structurally unrelated substances. In the following, different possibilities of the modulation of this multidrug-resistance are discussed. Part I deals with modulation of multidrug resistance by pharmacological drugs. Part II will be published in the next number of this journal and will discuss the following approaches: 1. Reduction of MDR in vivo after discontinuation of chemotherapy, 2. Investigations for inhibition of the development of MDR, 3. Circumvention of MDR by oligodesoxynucleotides as inhibitors of MDR gene expression, and 4. Inhibition of MDR by anti-P-glycoprotein monoclonal antibodies.