Cell
Volume 149, Issue 5, 25 May 2012, Pages 979-993
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Article
Mutational Processes Molding the Genomes of 21 Breast Cancers

https://doi.org/10.1016/j.cell.2012.04.024Get rights and content
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Summary

All cancers carry somatic mutations. The patterns of mutation in cancer genomes reflect the DNA damage and repair processes to which cancer cells and their precursors have been exposed. To explore these mechanisms further, we generated catalogs of somatic mutation from 21 breast cancers and applied mathematical methods to extract mutational signatures of the underlying processes. Multiple distinct single- and double-nucleotide substitution signatures were discernible. Cancers with BRCA1 or BRCA2 mutations exhibited a characteristic combination of substitution mutation signatures and a distinctive profile of deletions. Complex relationships between somatic mutation prevalence and transcription were detected. A remarkable phenomenon of localized hypermutation, termed “kataegis,” was observed. Regions of kataegis differed between cancers but usually colocalized with somatic rearrangements. Base substitutions in these regions were almost exclusively of cytosine at TpC dinucleotides. The mechanisms underlying most of these mutational signatures are unknown. However, a role for the APOBEC family of cytidine deaminases is proposed.

Highlights

► The genomes of 21 breast cancers sequenced ► Multiple somatic mutational processes extracted from mutation catalogs ► Mutational processes of BRCA1/BRCA2 breast cancers are distinctive ► Localized regions of hypermutation, “kataegis,” are frequent in breast cancers

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