Association of a germline copy number polymorphism of APOBEC3A and APOBEC3B with burden of putative APOBEC-dependent mutations in breast cancer.

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Nik-Zainal, Serena 
Wedge, David C 
Alexandrov, Ludmil B 
Petljak, Mia 
Butler, Adam P 

The somatic mutations in a cancer genome are the aggregate outcome of one or more mutational processes operative through the lifetime of the individual with cancer. Each mutational process leaves a characteristic mutational signature determined by the mechanisms of DNA damage and repair that constitute it. A role was recently proposed for the APOBEC family of cytidine deaminases in generating particular genome-wide mutational signatures and a signature of localized hypermutation called kataegis. A germline copy number polymorphism involving APOBEC3A and APOBEC3B, which effectively deletes APOBEC3B, has been associated with modestly increased risk of breast cancer. Here we show that breast cancers in carriers of the deletion show more mutations of the putative APOBEC-dependent genome-wide signatures than cancers in non-carriers. The results suggest that the APOBEC3A-APOBEC3B germline deletion allele confers cancer susceptibility through increased activity of APOBEC-dependent mutational processes, although the mechanism by which this increase in activity occurs remains unknown.

Breast Neoplasms, Cytidine Deaminase, DNA Copy Number Variations, Female, Genetic Markers, Genetic Predisposition to Disease, Humans, Minor Histocompatibility Antigens, Mutagenesis, Proteins, Sequence Deletion
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Nat Genet
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Nature Publishing Group
European Commission (242006)
We would like to thank the Wellcome Trust for support (grant reference 098051). SN-Z is a Wellcome-Beit Prize Fellow and is supported through a Wellcome Trust Intermediate Fellowship (grant reference WT100183MA). PJC is personally funded through a Wellcome Trust Senior Clinical Research Fellowship (grant reference WT088340MA). NB is an EHA fellow and is supported by a Lady Tata Memorial Trust award. The H.L. Holmes Award from the National Research Council Canada and an EMBO Fellowship supports AS.