DNA double-strand breaks (DSBs) prevent cells from entering mitosis allowing cells to repair their genomic damage. Little is known about the response to DSBs once cells have already committed to mitosis. Here, we review the genome-protective role of the mitotic DNA damage response (DDR) and evidence suggesting that its untimely activation induces chromosome segregation errors and paradoxically undermines genomic integrity. In contrast to normal cells, cancer cells coopt this pathway to propagate structural and numerical chromosomal instabilities. Cells derived from genomically unstable tumors exhibit evidence for a partially activated DDR during mitosis, which leads to ongoing chromosome segregation errors. Thus, a thorough understanding of the consequences of mitotic DNA damage is key to our ability to devise novel anticancer therapeutic strategies.

DNA双链断裂（DSB）可防止细胞进入有丝分裂，从而使细胞修复其基因组损伤。一旦细胞已经承诺有丝分裂，对DSB的反应知之甚少。在这里，我们审查了有丝分裂DNA损伤反应（DDR）的基因组保护作用，并有证据表明它的不合时宜的激活会诱发染色体分离错误，并且自相矛盾地破坏了基因组完整性。与正常细胞相反，癌细胞采用这种途径来传播结构和数值上的染色体不稳定性。从基因组不稳定的肿瘤衍生的细胞显示出有丝分裂期间部分激活的DDR的证据，这导致了正在进行的染色体分离错误。从而，