ERBB2 and breast cancer: Modi et al. performed a retrospective analysis of four clinical trials that enroled HER2+ BC patients (unknown ER/PR status) and found an indication of a shorter PFS associated with the use of β-blockers (HR = 1.10, 95% CI: 0.92–1.30) [18], similar to our findings for BC-specific survival in patients with HER2+ receptor status.