现已确知,非随机性染色体异常是人类肿瘤、特别是白血病和淋巴瘤的特征。近两年来,很多原肿瘤基因与转化基因已定位于特异性结构重排的染色体断裂点上。最近的实验还证明:位于这些断裂点处的基因在肿瘤发生中起着不可缺少的作用。更有趣的是,人类肿瘤特异性染色体重排的断裂点与遗传及普通脆性部位相一致。有些具有特异性染色体变化的肿瘤病人也是同一染色体位点上脆性部位的携带者。这样看来,脆性部位在人类肿瘤遗传易感 It is now known that non-randomized chromosomal abnormalities are characteristic of human tumors, particularly leukemias and lymphomas. In the past two years, many of the original tumor genes and transforming genes have been mapped to chromosome breakpoints in specific structural rearrangements. Recent experiments have also demonstrated that genes located at these breakpoints play an indispensable role in tumorigenesis. What is even more interesting is that the breakpoints of human tumor-specific chromosomal rearrangements are consistent with genetic and common fragile sites. Some tumor patients with specific chromosome changes are carriers of the fragile sites at the same chromosomal locus. In this way, the fragile parts are genetically susceptible to human tumors.