ERBB2 and neoplasm: HER2 is primarily overexpressed by tumor cells, but it is also expressed at low levels in normal tissues, particularly in cardiomyocytes (Press et al., 1990; Fuchs et al., 2003), entailing a risk of cardiotoxicity following anti-HER2 therapy (Slamon et al., 2001; Dempsey et al., 2021; Gonciar et al., 2021).