HER2‐negativity has been traditionally classified as IHC 1+ or 2+ in the absence of HER2 gene amplification by FISH; however, a new nomenclature has been proposed for HER2‐negative breast cancers that exhibit low HER2 expression, namely HER2‐low and HER2‐ultralow.21 This evidence concerns the gene ERBB2 and breast carcinoma.