ABT1 and major depressive disorder: In our downstream analysis performed to explore these alternatives, 17 pleiotropic loci between depression and BC were identified, harboring genes which were previously implicated in neural development and brain functions (i.e., HCN1, ABT1, ZSCAN12, ZNF184, KLC1, MKL1, SGSM3, CCDC91), or biological processes related to tumor growth (i.e., ABT1, ZSCAN12, ZNF184, KLC1, TTC28, MKL1, CCDC91, OLFM4, DDR1).