The ASCO/CAP guidelines from 2013 state that breast cancers with aggregations of HER2‐amplified cells (with HER2/CEP17 ratio > 2.0 or more than six HER2 copies per cell) in more than 10% of the tumor must be quantified and reported separately (Wolff et al., 2013). Here, ERBB2 is linked to breast cancer.