ERBB2 and breast cancer: This has important ramifications as an analysis published by Copeland-Halperin et al. in 2020 showed that holding trastuzumab for 6 weeks or longer -owing to cardiotoxicity- increases the risk of invasive breast cancer recurrence or death, with an adjusted hazard ratio (HR) of 1.56% (95% CI, 1.10–2.21), in patients with early-stage human epidermal growth factor receptor 2 (ERBB2)-positive breast cancer [14].