These researchers have recently shown that the DNA cytosine deaminase APOBEC3B is a probable source of somatic C-to-T mutations in breast cancer. APOBEC3B messenger RNA is upregulated in most primary breast tumors and breast cancer cell lines and endogenous APOBEC3B protein is predominantly nuclear and the only detectable source of DNA C-to-U editing activity in breast cancer cell-line extracts. This research was published in Nature in 2013.
Extending their initial analyses, the researchers recently addressed whether APOBEC3B is broadly responsible for mutagenesis in multiple tumor types. They analyzed gene expression data and mutation patterns, distributions and loads for 19 different cancer types, with over 4,800 exomes and 1,000,000 somatic mutations using public TCGA data. They showed that APOBEC3B is upregulated, and its preferred target sequence is frequently mutated and clustered in at least six distinct cancers: bladder, cervix, lung (adenocarcinoma and squamous cell carcinoma), head and neck, and breast. This work was published in Nature Genetics in 2013. The group has also shown that certain haplotypes of APOBEC3H may also play a role in breast, lung, and other cancers; this research was published in Nature Communications in 2016.