In this study, we observed CCNE1, NPBWR1 (Neuropeptides B/W receptor 1), SLC4A4 (Solute Carrier Family 4 member 4), MAOA (Monoamine oxidase A), A2ML1 (Alpha-2-macroglobulin like 1) and TTK (dual specificity protein kinase) not only significantly expressed in BRCA1/2-mutant breast cancer compared with wild-type BC and normal tissue, but also showed significant prognostic value for breast cancer (shown in Figs. 5A–5F). This evidence concerns the gene MAOA and breast cancer.