In the meta-analysis for BC-specific survival, HRs for use of β-blockers compared to no use were 1.04 (95% CI: 0.93–1.16) for luminal BC (combining luminal A and luminal B), 1.16 (95% CI: 0.77–1.75) for HER2+ BC, and 0.74 (95% CI: 0.55–1.00) for TNBC (Fig. 4). This evidence concerns the gene ERBB2 and breast cancer.