Breaking News on Fragile Sites in Cancer

Chromosome rearrangements in B lymphocytes can be initiated by AID-associated double strand breaks (DSBs), with others arising by unclear mechanisms. A recent study by Barlow and colleagues in Cell reports on genomic regions, termed early replicating fragile sites, that may explain many AID-independent DSBs and creates a compelling link between replication stress, transcription, and chromosome rearrangements