ERBB2 and breast cancer: Although propranolol increased antitumor activity of trastuzumab by resensitizing tumor cells in preclinical trials [40], yet βeta-blockers use was associated with worse OS in patients receiving anti-HER2 therapy for advanced breast cancer regardless of any cardiovascular disease status as reported from a pool analysis of EMILIA, TH3RESA, MARIANNE, and CLEOPATRA clinical trials [41].