[Strategies for the overcoming of drug resistance].

The purpose of the studies for drug resistance could be summarized in the following four points. 1) Mechanisms of acquired drug resistance can be translated to those of inherent resistance. 2) Molecular targets of anticancer drugs can be clarified and accurate application of methods for the overcoming of drug resistance may be possible. 3) Important hints can be obtained for the development of new anticancer agents against molecular targets. 4) Efficient methods can be provided to find new anticancer agents against drug refractory tumors. The clinical strategies for the overcoming of drug resistance are 1) the use of non cross-resistant drugs, 2) the application of the drugs for overcoming resistance, 3) high dose chemotherapy, and 4) the combined use of radiotherapy and surgery.