肿瘤细胞具有原发性耐药或对已接触过抗肿瘤药物无论在功能上或结构上都不相关的多种药物具有获得性耐药 ,这种现象被称为多药耐药 (ＭＤＲ)。多药耐药降低了抗肿瘤药物的疗效。尽管临床上肿瘤细胞的耐药可有多种不同的分子机制 ,如ｐ5 3基因突变、Ｂｃｌ 2水平上调和ＤＮＡ修 Tumor cells have acquired primary resistance or have acquired resistance to a variety of drugs that have been exposed to antitumor drugs, either functionally or structurally, and this phenomenon is called multidrug resistance (MDR). Multidrug resistance reduces the efficacy of antitumor drugs. Although clinically there are many different molecular mechanisms of drug resistance in tumor cells, such as mutation of p5 3 gene, upregulation of Bcl 2 level and DNA repair