Interestingly, in a publically available SNP array data set of 344 breast cancers (accession number EGAS00001001178 [33]), APOBEC3A copy number status was equal to APOBEC3B copy number status in all tumors, suggesting that APOBEC3A is always amplified or deleted simultaneously with APOBEC3B during breast tumorigenesis. The gene discussed is APOBEC3A; the disease is breast cancer.