ERBB2 and breast cancer: In this analysis, the HRs for use of β-blockers compared to no use for PFS/RFS were 1.13 (95% CI: 0.86–1.49) for luminal BC (combining luminal A and luminal B) and 0.60 (95% CI: 0.36–1.00) for TNBC, while for BC-specific survival, HRs were 1.03 (95% CI: 0.93–1.13) for luminal BC (combing luminal A and luminal B), 1.19 (95% CI: 0.84–1.70) for HER2+ BC, and 0.78 (95% CI: 0.52–1.16) for TNBC.