C5 is an even more potent inhibitor of stalled DNA replication fork restart and of over-resection of nascent DNA in cells defective in replication fork protection, including those with mutations in BRCA2, RAD51 and BOD1L. Notably, DNA2 inhibitors also show cancer cell killing effects that are synergistic with PARP inhibitors (75), which have excited the field as they are synthetic lethal with BRCA1 and BRCA2 deficiencies (188,189). Here, DNA2 is linked to cancer.