Although we cannot completely rule out the possibility of involving other cellular pathways that are affected by 53BP1 deficiency in cells, our conclusions provide an explanation to previous observations that were not clearly answered using a traditional model of 53BP1-mediated DSB repair: how 53BP1 contributes to the recovery of stalled replication forks (23–25) and how 53BP1 dysregulation leads to genomic instability and the development of cancer (45,61,66,69). The gene discussed is TP53BP1; the disease is cancer.