Just as the proportion of HER2-low breast cancers varied from 16.2 (Jacot et al. 2021) to 64.4% (Horisawa et al. 2022), some studies showed improved survival for HER2-low patients whereas others described rather negative clinical effects (Alves et al. 2022; de Moura Leite et al. 2021; Horisawa et al. 2022; Tan et al. 2022; Won et al. 2022). The gene discussed is ERBB2; the disease is breast carcinoma.