引言美登素系一种具有抗肿瘤作用的天然产生的柄型大环内酯。它象长春碱、长春新碱一样,也具有中期阻滞抗有丝分裂的特征。临床前啮齿动物的抗肿瘤试验证明低剂量就有高的活性,且在很宽的剂量范围内有抗肿瘤作用。目前美国国立肿瘤研究所已大部分 Foreword Maytansine is a naturally occurring acyclic macrolide with anti-tumor effects. It, like vinblastine, vincristine, also has mid-term block anti-mitotic characteristics. Preclinical rodent antitumor tests have shown high activity at low doses and antitumor effects over a wide range of doses. At present, the United States National Cancer Institute has been most