In contrast, the proportion of 2+ IHC that were HER2 amplified, as detected by CISH, was 73.5%, which is lower than previously reported (93%).39 The 26.5% (26/98) IHC-equivocal/HER2 non-amplified tumours in this study, all of which had 2+ IHC scores, is higher than the result obtained by other studies on invasive tumours.40–42 The concordance between 0/1+ IHC and HER2 non-amplified tumours was 99.7%. The gene discussed is ERBB2; the disease is neoplasm.