This variant tags a common, approximately 30-kb germline SV that deletes the APOBEC3B coding sequence and fuses the APOBEC3B 3′ untranslated region with the coding sequence of APOBEC3A. The deletion is known to increase breast cancer risk and APOBEC mutagenesis in breast cancer genomes66,67. This evidence concerns the gene APOBEC3B and breast cancer.