In addition, several new targeted agents for treating HER2-positive BC have recently been introduced including the TKI tucatinib (Tukysa; Cascadian Therapeutics) (Murthy et al. 2020) and fam-trastuzumab deruxtecan-nxki (Enhirtu, Roche), an ADC that links trastuzumab to a potent topoisomerase I inhibitor (Martinez-Saez and Prat 2021). Here, ERBB2 is linked to breast cancer.