Fig. 1.

Genome stability is dependent on faithful DNA repair and chromosome segregation during cell division. During S phase, the centrosome and genomic material are replicated concurrently, and replication errors are repaired prior to mitotic entry (1). During mitosis, equal segregation of chromosomes requires a bipolar mitotic spindle, telomere preservation and the completion of the spindle assembly checkpoint. Ectopic amplification of centrosomes (2), telomerase dysfunction (3) and failure of the spindle assembly checkpoint (4) may result in aborted mitosis. Mitotic failure gives rise to a single tetraploid cell (4 N) instead of two diploid cells (2 N). This tetraploid cell can progress through the cell cycle should the TP53-dependent post mitotic checkpoint fail to induce apoptosis or senescence (4). Thus, genomic instability is propagated in subsequent cell cycles.